Global Invasion History of the Fire Ant Solenopsis invicta
Marina S. Ascunce1,2,*, Chin-Cheng Yang1,3,*, Jane Oakey4, Luis Calcaterra5, Wen-Jer Wu3, Cheng-Jen Shih3, Jérôme Goudet6, Kenneth G. Ross7, and DeWayne Shoemaker1,†
Abstract
The fire ant Solenopsis invicta is a significant pest that was inadvertently introduced into the southern United States almost a century ago and more recently into California and other regions of the world. An assessment of genetic variation at a diverse set of molecular markers in 2144 fire ant colonies from 75 geographic sites worldwide revealed that at least nine separate introductions of S. invicta have occurred into newly invaded areas and that the main southern U.S. population is probably the source of all but one of these introductions. The sole exception involves a putative serial invasion from the southern United States to California to Taiwan. These results illustrate in stark fashion a severe negative consequence of an increasingly massive and interconnected global trade and travel system.
Science 25 February 2011: Vol. 331 no. 6020 pp. 1066-1068
Friday, February 25, 2011
Thursday, February 24, 2011
Seaweed digestion!!
Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota.
Hehemann JH, Correc G, Barbeyron T, Helbert W, Czjzek M, Michel G.
Université Pierre et Marie Curie, Paris, France.
Abstract
Gut microbes supply the human body with energy from dietary polysaccharides through carbohydrate active enzymes, or CAZymes, which are absent in the human genome. These enzymes target polysaccharides from terrestrial plants that dominated diet throughout human evolution. The array of CAZymes in gut microbes is highly diverse, exemplified by the human gut symbiont Bacteroides thetaiotaomicron, which contains 261 glycoside hydrolases and polysaccharide lyases, as well as 208 homologues of susC and susD-genes coding for two outer membrane proteins involved in starch utilization. A fundamental question that, to our knowledge, has yet to be addressed is how this diversity evolved by acquiring new genes from microbes living outside the gut. Here we characterize the first porphyranases from a member of the marine Bacteroidetes, Zobellia galactanivorans, active on the sulphated polysaccharide porphyran from marine red algae of the genus Porphyra. Furthermore, we show that genes coding for these porphyranases, agarases and associated proteins have been transferred to the gut bacterium Bacteroides plebeius isolated from Japanese individuals. Our comparative gut metagenome analyses show that porphyranases and agarases are frequent in the Japanese population and that they are absent in metagenome data from North American individuals. Seaweeds make an important contribution to the daily diet in Japan (14.2 g per person per day), and Porphyra spp. (nori) is the most important nutritional seaweed, traditionally used to prepare sushi. This indicates that seaweeds with associated marine bacteria may have been the route by which these novel CAZymes were acquired in human gut bacteria, and that contact with non-sterile food may be a general factor in CAZyme diversity in human gut microbes.
Nature. 2010 Apr 8;464(7290):908-12.
Hehemann JH, Correc G, Barbeyron T, Helbert W, Czjzek M, Michel G.
Université Pierre et Marie Curie, Paris, France.
Abstract
Gut microbes supply the human body with energy from dietary polysaccharides through carbohydrate active enzymes, or CAZymes, which are absent in the human genome. These enzymes target polysaccharides from terrestrial plants that dominated diet throughout human evolution. The array of CAZymes in gut microbes is highly diverse, exemplified by the human gut symbiont Bacteroides thetaiotaomicron, which contains 261 glycoside hydrolases and polysaccharide lyases, as well as 208 homologues of susC and susD-genes coding for two outer membrane proteins involved in starch utilization. A fundamental question that, to our knowledge, has yet to be addressed is how this diversity evolved by acquiring new genes from microbes living outside the gut. Here we characterize the first porphyranases from a member of the marine Bacteroidetes, Zobellia galactanivorans, active on the sulphated polysaccharide porphyran from marine red algae of the genus Porphyra. Furthermore, we show that genes coding for these porphyranases, agarases and associated proteins have been transferred to the gut bacterium Bacteroides plebeius isolated from Japanese individuals. Our comparative gut metagenome analyses show that porphyranases and agarases are frequent in the Japanese population and that they are absent in metagenome data from North American individuals. Seaweeds make an important contribution to the daily diet in Japan (14.2 g per person per day), and Porphyra spp. (nori) is the most important nutritional seaweed, traditionally used to prepare sushi. This indicates that seaweeds with associated marine bacteria may have been the route by which these novel CAZymes were acquired in human gut bacteria, and that contact with non-sterile food may be a general factor in CAZyme diversity in human gut microbes.
Nature. 2010 Apr 8;464(7290):908-12.
Wednesday, February 23, 2011
Ulcers caused by H. pylori!!!
Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration.
Marshall BJ, Warren JR.
Abstract
Biopsy specimens were taken from intact areas of antral mucosa in 100 consecutive consenting patients presenting for gastroscopy. Spiral or curved bacilli were demonstrated in specimens from 58 patients. Bacilli cultured from 11 of these biopsies were gram-negative, flagellate, and microaerophilic and appeared to be a new species related to the genus Campylobacter. The bacteria were present in almost all patients with active chronic gastritis, duodenal ulcer, or gastric ulcer and thus may be an important factor in the aetiology of these diseases.
Lancet. 1984 Jun 16;1(8390):1311-5.
Marshall BJ, Warren JR.
Abstract
Biopsy specimens were taken from intact areas of antral mucosa in 100 consecutive consenting patients presenting for gastroscopy. Spiral or curved bacilli were demonstrated in specimens from 58 patients. Bacilli cultured from 11 of these biopsies were gram-negative, flagellate, and microaerophilic and appeared to be a new species related to the genus Campylobacter. The bacteria were present in almost all patients with active chronic gastritis, duodenal ulcer, or gastric ulcer and thus may be an important factor in the aetiology of these diseases.
Lancet. 1984 Jun 16;1(8390):1311-5.
Tuesday, February 22, 2011
AIDS is caused by a virus!!
Antibodies reactive with human T-lymphotropic retroviruses (HTLV-III) in the serum of patients with AIDS.
Abstract
In cats, infection with T-lymphotropic retroviruses can cause T-cell proliferation and leukemia or T-cell depletion and immunosuppression. In humans, some highly T4 tropic retroviruses called HTLV-I can cause T-cell proliferation and leukemia. The subgroup HTLV-II also induces T-cell proliferation in vitro, but its role in disease is unclear. Viruses of a third subgroup of human T-lymphotropic retroviruses, collectively designated HTLV-III, have been isolated from cultured cells of 48 patients with acquired immunodeficiency syndrome (AIDS). The biological properties of HTLV-III and immunological analyses of its proteins show that this virus is a member of the HTLV family, and that it is more closely related to HTLV-II than to HTLV-I. Serum samples from 88 percent of patients with AIDS and from 79 percent of homosexual men with signs and symptoms that frequently precede AIDS, but from less than 1 percent of heterosexual subjects, have antibodies reactive against antigens of HTLV-III. The major immune reactivity appears to be directed against p41, the presumed envelope antigen of the virus.Science. 1984 May 4;224(4648):506-8.
Detection, isolation, and continuous production of cytopathic retroviruses (HTLV-III) from patients with AIDS and pre-AIDS.
Abstract
A cell system was developed for the reproducible detection of human T-lymphotropic retroviruses (HTLV family) from patients with the acquired immunodeficiency syndrome (AIDS) or with signs or symptoms that frequently precede AIDS (pre-AIDS). The cells are specific clones from a permissive human neoplastic T-cell line. Some of the clones permanently grow and continuously produce large amounts of virus after infection with cytopathic (HTLV-III) variants of these viruses. One cytopathic effect of HTLV-III in this system is the arrangement of multiple nuclei in a characteristic ring formation in giant cells of the infected T-cell population. These structures can be used as an indicator to detect HTLV-III in clinical specimens. This system opens the way to the routine detection of HTLV-III and related cytopathic variants of HTLV in patients with AIDS or pre-AIDS and in healthy carriers, and it provides large amounts of virus for detailed molecular and immunological analyses.Science. 1984 May 4;224(4648):497-500.
Monday, February 21, 2011
Neanderthal Genome!!
Sequencing and analysis of Neanderthal genomic DNA.
Noonan JP, Coop G, Kudaravalli S, Smith D, Krause J, Alessi J, Chen F, Platt D, Pääbo S, Pritchard JK, Rubin EM.
U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598, USA.
Abstract
Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we must make inferences about their biology, behavior, and relationship to ourselves. Here, we describe the characterization of these extinct hominids from a new perspective, based on the development of a Neanderthal metagenomic library and its high-throughput sequencing and analysis. Several lines of evidence indicate that the 65,250 base pairs of hominid sequence so far identified in the library are of Neanderthal origin, the strongest being the ascertainment of sequence identities between Neanderthal and chimpanzee at sites where the human genomic sequence is different. These results enabled us to calculate the human-Neanderthal divergence time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor approximately 706,000 years ago, and that the human and Neanderthal ancestral populations split approximately 370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.
Science. 2006 Nov 17;314(5802):1113-8.
Noonan JP, Coop G, Kudaravalli S, Smith D, Krause J, Alessi J, Chen F, Platt D, Pääbo S, Pritchard JK, Rubin EM.
U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598, USA.
Abstract
Our knowledge of Neanderthals is based on a limited number of remains and artifacts from which we must make inferences about their biology, behavior, and relationship to ourselves. Here, we describe the characterization of these extinct hominids from a new perspective, based on the development of a Neanderthal metagenomic library and its high-throughput sequencing and analysis. Several lines of evidence indicate that the 65,250 base pairs of hominid sequence so far identified in the library are of Neanderthal origin, the strongest being the ascertainment of sequence identities between Neanderthal and chimpanzee at sites where the human genomic sequence is different. These results enabled us to calculate the human-Neanderthal divergence time based on multiple randomly distributed autosomal loci. Our analyses suggest that on average the Neanderthal genomic sequence we obtained and the reference human genome sequence share a most recent common ancestor approximately 706,000 years ago, and that the human and Neanderthal ancestral populations split approximately 370,000 years ago, before the emergence of anatomically modern humans. Our finding that the Neanderthal and human genomes are at least 99.5% identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences from metagenomic libraries. This initial analysis of the Neanderthal genome advances our understanding of the evolutionary relationship of Homo sapiens and Homo neanderthalensis and signifies the dawn of Neanderthal genomics.
Science. 2006 Nov 17;314(5802):1113-8.
Sunday, February 20, 2011
Review: CORRELATED GENOTYPES!
I'm not sure what the best format is conveying this information, so we will make changes as necessary.
The Introduction
First, what is being addressed in this paper? Fowler et al. are looking to investigate whether "variation in specific genes might be relevant to the process of friend selection or, distinctly, whether the process of choosing friends might result in correlated genotypes between friends." Specifically, they are examining "phenotypic similarity between individuals connected in a social network is reflected in their genotypes." For those who are not sure what a "genotype" is, for this article they are referring to a DNA sequence at a particular location in the human genome. Also, a phenotype is the manifestation of having a particular genotype. Phenotype can be mean hair color and height and things like that, but it can also mean intelligence, age to puberty, and other such things.
The authors point out that there are genetic correlations between kin groups and this has been show in many diverse organisms, but this may not be the "only basis on which natural selection might possibly operate at the group level." The possibility of a non-kin selection basis has long been postulated, but no data has previously been reported. If we understand the phenotype to be under the direct action of one's own genome, then it would certainly be remarkable if our friend's genomes was shaping our phenotype.
It is a known fact that people associate with people that they resemble (phenotypically similar to one another), so one needs to be aware of situations in which phenotypic similarity can result without being caused by influence from friend genomes.
1. A trivial by-product of a group of people being unable to move away from one another. Imagine an isolated tribe in the Amazon.
2. "People may actively choose friends of a similar genotype." Of course, people cannot see their friend's genotypes, but phenotype is a direct consequence of genotypes and as such they could be picking a certain set of genotypes. The authors give an example of skinny people befriending skinny people, which percludes genetic based obesity phenotypes.
3. Behaviorial phenotypes may induce one to seek out environments where they will encounter people of similar phenotypes and by extension similar genotypes. The author's note that this could occur with distance runners who join clubs or go to events where they will meet other distance runners.
4. The environment of similar phenotypes may pull a similar phenotype in as is the case with college admission.
The Data
Let me upfront about this, I have very little training in statistics and as such this paper is very difficult to analyze. So, I will probably just tell you what they did, but I cannot go into more than that.
The researchers started with the Add Health dataset (National Longitudinal Study of Adolescent Health) which is data from a study that "explores the causes of health related behavior of adolescents in grades 7 through 12 and their outcomes in young adulthood." In this study, each student nominated up to 5 male and 5 female friends and the details of those friendships. Every student and their friends were swabbed and genotyped for the following genes:
CYP2A6- cytochrome p450 2A6
DRD2- dopamine D2 receptor
DRD4- dopamine D4 receptor
MAOA- monoamine oxidase A-uVNTR
SLC6A3- Dopamine transporter
SLC6A4- Serotonin transporter
I cannot show you the social network figures from the actual paper, because of copyright issues and my lack of what is ok to publish, but they show two social networks showing postive genotypic correlation for DRD2 and negative genotypic correlation for CYP2A6. The trend that they saw was replicated by statistical analysis of a different dataset (Framingham Heart Study Social Network) where they saw similar trends of similar magnitude.
The Discussion
It is possible that the trends seen are because of association between genes, but this is unlikely because associating genes are very rare.
Why were these genotypes postitively correlated (DRD2) or negatively correlated (CYP2A6)? The authors point to evidence that DRD2 has been associated with alcoholism and it s fairly straightforward to see that alcoholics are avoided by non-alcoholics and that alcoholics associate in environments that non-alcoholics avoid.
The personality traits attributable to CYP2A6 are not known at this time, but it has been implicated in personality traits.
This research highlights the overestimation of genetic effects that has occurred because previous research was not aware the effect that friend genotypes could have on one's phenotype. The author's give an example of a woman predisposed to drink because of her own genotype, but also because of her friend's genotypes, which makes them more likely to drink.
The most interesting idea presented, at least to me, is the idea of humans as "metagenomic." This means that "we could possibly view an individual's genetic landscape as a summation of the genes within the individual and those around him, just as in certain other organisms."
Overall, I found this to be a great read and would very much like to understand the statistics behind the conclusions. The field is still young and there are many questions to ask!
The Introduction
First, what is being addressed in this paper? Fowler et al. are looking to investigate whether "variation in specific genes might be relevant to the process of friend selection or, distinctly, whether the process of choosing friends might result in correlated genotypes between friends." Specifically, they are examining "phenotypic similarity between individuals connected in a social network is reflected in their genotypes." For those who are not sure what a "genotype" is, for this article they are referring to a DNA sequence at a particular location in the human genome. Also, a phenotype is the manifestation of having a particular genotype. Phenotype can be mean hair color and height and things like that, but it can also mean intelligence, age to puberty, and other such things.
The authors point out that there are genetic correlations between kin groups and this has been show in many diverse organisms, but this may not be the "only basis on which natural selection might possibly operate at the group level." The possibility of a non-kin selection basis has long been postulated, but no data has previously been reported. If we understand the phenotype to be under the direct action of one's own genome, then it would certainly be remarkable if our friend's genomes was shaping our phenotype.
It is a known fact that people associate with people that they resemble (phenotypically similar to one another), so one needs to be aware of situations in which phenotypic similarity can result without being caused by influence from friend genomes.
1. A trivial by-product of a group of people being unable to move away from one another. Imagine an isolated tribe in the Amazon.
2. "People may actively choose friends of a similar genotype." Of course, people cannot see their friend's genotypes, but phenotype is a direct consequence of genotypes and as such they could be picking a certain set of genotypes. The authors give an example of skinny people befriending skinny people, which percludes genetic based obesity phenotypes.
3. Behaviorial phenotypes may induce one to seek out environments where they will encounter people of similar phenotypes and by extension similar genotypes. The author's note that this could occur with distance runners who join clubs or go to events where they will meet other distance runners.
4. The environment of similar phenotypes may pull a similar phenotype in as is the case with college admission.
The Data
Let me upfront about this, I have very little training in statistics and as such this paper is very difficult to analyze. So, I will probably just tell you what they did, but I cannot go into more than that.
The researchers started with the Add Health dataset (National Longitudinal Study of Adolescent Health) which is data from a study that "explores the causes of health related behavior of adolescents in grades 7 through 12 and their outcomes in young adulthood." In this study, each student nominated up to 5 male and 5 female friends and the details of those friendships. Every student and their friends were swabbed and genotyped for the following genes:
CYP2A6- cytochrome p450 2A6
DRD2- dopamine D2 receptor
DRD4- dopamine D4 receptor
MAOA- monoamine oxidase A-uVNTR
SLC6A3- Dopamine transporter
SLC6A4- Serotonin transporter
I cannot show you the social network figures from the actual paper, because of copyright issues and my lack of what is ok to publish, but they show two social networks showing postive genotypic correlation for DRD2 and negative genotypic correlation for CYP2A6. The trend that they saw was replicated by statistical analysis of a different dataset (Framingham Heart Study Social Network) where they saw similar trends of similar magnitude.
The Discussion
It is possible that the trends seen are because of association between genes, but this is unlikely because associating genes are very rare.
Why were these genotypes postitively correlated (DRD2) or negatively correlated (CYP2A6)? The authors point to evidence that DRD2 has been associated with alcoholism and it s fairly straightforward to see that alcoholics are avoided by non-alcoholics and that alcoholics associate in environments that non-alcoholics avoid.
The personality traits attributable to CYP2A6 are not known at this time, but it has been implicated in personality traits.
This research highlights the overestimation of genetic effects that has occurred because previous research was not aware the effect that friend genotypes could have on one's phenotype. The author's give an example of a woman predisposed to drink because of her own genotype, but also because of her friend's genotypes, which makes them more likely to drink.
The most interesting idea presented, at least to me, is the idea of humans as "metagenomic." This means that "we could possibly view an individual's genetic landscape as a summation of the genes within the individual and those around him, just as in certain other organisms."
Overall, I found this to be a great read and would very much like to understand the statistics behind the conclusions. The field is still young and there are many questions to ask!
Wednesday, February 16, 2011
Self Control!!
A gradient of childhood self-control predicts health, wealth, and public safety
Terrie E. Moffitta,b, Louise Arseneaultb, Daniel Belskya, Nigel Dicksonc, Robert J. Hancoxc, HonaLee Harringtona, Renate Houtsa, Richie Poultonc, Brent W. Robertsd, Stephen Rossa, Malcolm R. Searse,f, W. Murray Thomsong, and Avshalom Caspia,b,1
+ Author Affiliations
aDepartments of Psychology and Neuroscience and Psychiatry and Behavioral Sciences, and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27705;
bSocial, Genetic, and Developmental Psychiatry Research Centre, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom;
cDunedin Multidisciplinary Health and Development Research Unit, Department of Preventive and Social Medicine, School of Medicine, and
gDepartment of Oral Sciences and Orthodontics, School of Dentistry, University of Otago, Dunedin, New Zealand;
dDepartment of Psychology, University of Illinois, Urbana-Champaign, Champaign, IL 61820;
eDepartment of Medicine, McMaster University, Hamilton, ON, L8S4L8 Canada; and
fFirestone Institute for Respiratory Health, Hamilton, ON, Canada L8N 4A6
Abstract
Policy-makers are considering large-scale programs aimed at self-control to improve citizens’ health and wealth and reduce crime. Experimental and economic studies suggest such programs could reap benefits. Yet, is self-control important for the health, wealth, and public safety of the population? Following a cohort of 1,000 children from birth to the age of 32 y, we show that childhood self-control predicts physical health, substance dependence, personal finances, and criminal offending outcomes, following a gradient of self-control. Effects of children's self-control could be disentangled from their intelligence and social class as well as from mistakes they made as adolescents. In another cohort of 500 sibling-pairs, the sibling with lower self-control had poorer outcomes, despite shared family background. Interventions addressing self-control might reduce a panoply of societal costs, save taxpayers money, and promote prosperity.
Proc. Natl. Acad. Sci. USA 2011 108 (7) 2639-2640
Terrie E. Moffitta,b, Louise Arseneaultb, Daniel Belskya, Nigel Dicksonc, Robert J. Hancoxc, HonaLee Harringtona, Renate Houtsa, Richie Poultonc, Brent W. Robertsd, Stephen Rossa, Malcolm R. Searse,f, W. Murray Thomsong, and Avshalom Caspia,b,1
+ Author Affiliations
aDepartments of Psychology and Neuroscience and Psychiatry and Behavioral Sciences, and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27705;
bSocial, Genetic, and Developmental Psychiatry Research Centre, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom;
cDunedin Multidisciplinary Health and Development Research Unit, Department of Preventive and Social Medicine, School of Medicine, and
gDepartment of Oral Sciences and Orthodontics, School of Dentistry, University of Otago, Dunedin, New Zealand;
dDepartment of Psychology, University of Illinois, Urbana-Champaign, Champaign, IL 61820;
eDepartment of Medicine, McMaster University, Hamilton, ON, L8S4L8 Canada; and
fFirestone Institute for Respiratory Health, Hamilton, ON, Canada L8N 4A6
Abstract
Policy-makers are considering large-scale programs aimed at self-control to improve citizens’ health and wealth and reduce crime. Experimental and economic studies suggest such programs could reap benefits. Yet, is self-control important for the health, wealth, and public safety of the population? Following a cohort of 1,000 children from birth to the age of 32 y, we show that childhood self-control predicts physical health, substance dependence, personal finances, and criminal offending outcomes, following a gradient of self-control. Effects of children's self-control could be disentangled from their intelligence and social class as well as from mistakes they made as adolescents. In another cohort of 500 sibling-pairs, the sibling with lower self-control had poorer outcomes, despite shared family background. Interventions addressing self-control might reduce a panoply of societal costs, save taxpayers money, and promote prosperity.
Proc. Natl. Acad. Sci. USA 2011 108 (7) 2639-2640
Weird animal genomes!
Weird animal genomes and the evolution of vertebrate sex and sex chromosomes.
Marshall Graves JA.
Research School of Biological Science, The Australian National University, Canberra, ACT 2601, Australia. jenny.graves@anu.edu.au
Abstract
Humans, mice, and even kangaroos have an XX female:XY male system of sex determination, in which the Y harbors a male-dominant sex-determining gene SRY. Birds have the opposite, ZZ males and ZW females, and may use a dosage-sensitive Z-borne gene. Other reptiles have genetic sex but no visible sex chromosomes, or determine sex by temperature of egg incubation. How can we make sense of so much variation? How do systems change in evolution? Studies of some unlikely animals-platypus and dragon lizards, frogs and fish-confirm that evolutionary transitions have occurred between TSD and GSD systems, between XY and ZW systems, and even between male and female heterogametic systems. Here I explore nonmodel systems that offer some new perspectives on some venerable questions of sex and sex chromosomes.
Annu Rev Genet. 2008;42:565-86.
Marshall Graves JA.
Research School of Biological Science, The Australian National University, Canberra, ACT 2601, Australia. jenny.graves@anu.edu.au
Abstract
Humans, mice, and even kangaroos have an XX female:XY male system of sex determination, in which the Y harbors a male-dominant sex-determining gene SRY. Birds have the opposite, ZZ males and ZW females, and may use a dosage-sensitive Z-borne gene. Other reptiles have genetic sex but no visible sex chromosomes, or determine sex by temperature of egg incubation. How can we make sense of so much variation? How do systems change in evolution? Studies of some unlikely animals-platypus and dragon lizards, frogs and fish-confirm that evolutionary transitions have occurred between TSD and GSD systems, between XY and ZW systems, and even between male and female heterogametic systems. Here I explore nonmodel systems that offer some new perspectives on some venerable questions of sex and sex chromosomes.
Annu Rev Genet. 2008;42:565-86.
Tuesday, February 15, 2011
HUMAN CHEMOSIGNALS!!
Human Tears Contain a Chemosignal
Shani Gelstein1,*, Yaara Yeshurun1,*, Liron Rozenkrantz1, Sagit Shushan1,2, Idan Frumin1, Yehudah Roth2 and Noam Sobel1,†
+ Author Affiliations
1Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
2Department of OtoRhinoLaryngology and Head and Neck Surgery, Edith Wolfson Medical Center, Holon 58100, Israel.
Abstract
Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion–related odorless tears obtained from women donors induced reductions in sexual appeal attributed by men to pictures of women’s faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women’s tears selectively reduced activity in brain substrates of sexual arousal in men.
Science 14 January 2011: Vol. 331 no. 6014 pp. 226-230
Shani Gelstein1,*, Yaara Yeshurun1,*, Liron Rozenkrantz1, Sagit Shushan1,2, Idan Frumin1, Yehudah Roth2 and Noam Sobel1,†
+ Author Affiliations
1Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
2Department of OtoRhinoLaryngology and Head and Neck Surgery, Edith Wolfson Medical Center, Holon 58100, Israel.
Abstract
Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion–related odorless tears obtained from women donors induced reductions in sexual appeal attributed by men to pictures of women’s faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women’s tears selectively reduced activity in brain substrates of sexual arousal in men.
Science 14 January 2011: Vol. 331 no. 6014 pp. 226-230
Monday, February 14, 2011
Human Genome Sequence!
Initial sequencing and analysis of the human genome.
Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, Baldwin J, Devon K, Dewar K, Doyle M, FitzHugh W, Funke R, Gage D, Harris K, Heaford A, Howland J, Kann L, Lehoczky J, LeVine R, McEwan P, McKernan K, Meldrim J, Mesirov JP, Miranda C, Morris W, Naylor J, Raymond C, Rosetti M, Santos R, Sheridan A, Sougnez C, Stange-Thomann N, Stojanovic N, Subramanian A, Wyman D, Rogers J, Sulston J, Ainscough R, Beck S, Bentley D, Burton J, Clee C, Carter N, Coulson A, Deadman R, Deloukas P, Dunham A, Dunham I, Durbin R, French L, Grafham D, Gregory S, Hubbard T, Humphray S, Hunt A, Jones M, Lloyd C, McMurray A, Matthews L, Mercer S, Milne S, Mullikin JC, Mungall A, Plumb R, Ross M, Shownkeen R, Sims S, Waterston RH, Wilson RK, Hillier LW, McPherson JD, Marra MA, Mardis ER, Fulton LA, Chinwalla AT, Pepin KH, Gish WR, Chissoe SL, Wendl MC, Delehaunty KD, Miner TL, Delehaunty A, Kramer JB, Cook LL, Fulton RS, Johnson DL, Minx PJ, Clifton SW, Hawkins T, Branscomb E, Predki P, Richardson P, Wenning S, Slezak T, Doggett N, Cheng JF, Olsen A, Lucas S, Elkin C, Uberbacher E, Frazier M, Gibbs RA, Muzny DM, Scherer SE, Bouck JB, Sodergren EJ, Worley KC, Rives CM, Gorrell JH, Metzker ML, Naylor SL, Kucherlapati RS, Nelson DL, Weinstock GM, Sakaki Y, Fujiyama A, Hattori M, Yada T, Toyoda A, Itoh T, Kawagoe C, Watanabe H, Totoki Y, Taylor T, Weissenbach J, Heilig R, Saurin W, Artiguenave F, Brottier P, Bruls T, Pelletier E, Robert C, Wincker P, Smith DR, Doucette-Stamm L, Rubenfield M, Weinstock K, Lee HM, Dubois J, Rosenthal A, Platzer M, Nyakatura G, Taudien S, Rump A, Yang H, Yu J, Wang J, Huang G, Gu J, Hood L, Rowen L, Madan A, Qin S, Davis RW, Federspiel NA, Abola AP, Proctor MJ, Myers RM, Schmutz J, Dickson M, Grimwood J, Cox DR, Olson MV, Kaul R, Raymond C, Shimizu N, Kawasaki K, Minoshima S, Evans GA, Athanasiou M, Schultz R, Roe BA, Chen F, Pan H, Ramser J, Lehrach H, Reinhardt R, McCombie WR, de la Bastide M, Dedhia N, Blöcker H, Hornischer K, Nordsiek G, Agarwala R, Aravind L, Bailey JA, Bateman A, Batzoglou S, Birney E, Bork P, Brown DG, Burge CB, Cerutti L, Chen HC, Church D, Clamp M, Copley RR, Doerks T, Eddy SR, Eichler EE, Furey TS, Galagan J, Gilbert JG, Harmon C, Hayashizaki Y, Haussler D, Hermjakob H, Hokamp K, Jang W, Johnson LS, Jones TA, Kasif S, Kaspryzk A, Kennedy S, Kent WJ, Kitts P, Koonin EV, Korf I, Kulp D, Lancet D, Lowe TM, McLysaght A, Mikkelsen T, Moran JV, Mulder N, Pollara VJ, Ponting CP, Schuler G, Schultz J, Slater G, Smit AF, Stupka E, Szustakowski J, Thierry-Mieg D, Thierry-Mieg J, Wagner L, Wallis J, Wheeler R, Williams A, Wolf YI, Wolfe KH, Yang SP, Yeh RF, Collins F, Guyer MS, Peterson J, Felsenfeld A, Wetterstrand KA, Patrinos A, Morgan MJ, de Jong P, Catanese JJ, Osoegawa K, Shizuya H, Choi S, Chen YJ; International Human Genome Sequencing Consortium.
Whitehead Institute for Biomedical Research, Center for Genome Research, Cambridge, Massachusetts 02142, USA. lander@genome.wi.mit.edu
Erratum in:- Nature 2001 Aug 2;412(6846):565.
- Nature 2001 Jun 7;411(6838):720. Szustakowki, J [corrected to Szustakowski, J].
- Nature. 2001 Feb 15;409(6822):818-20.
- Nature. 2001 Feb 15;409(6822):820-1.
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Abstract
The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.Nature. 2001 Feb 15;409(6822):860-921.
Saturday, February 12, 2011
Correlated genotypes in friendship networks!
Correlated genotypes in friendship networks
+Author Affiliations- Edited by Gene E. Robinson, University of Illinois, Urbana, IL, and approved December 15, 2010 (received for review August 6, 2010)
Abstract
It is well known that humans tend to associate with other humans who have similar characteristics, but it is unclear whether this tendency has consequences for the distribution of genotypes in a population. Although geneticists have shown that populations tend to stratify genetically, this process results from geographic sorting or assortative mating, and it is unknown whether genotypes may be correlated as a consequence of nonreproductive associations or other processes. Here, we study six available genotypes from the National Longitudinal Study of Adolescent Health to test for genetic similarity between friends. Maps of the friendship networks show clustering of genotypes and, after we apply strict controls for population stratification, the results show that one genotype is positively correlated (homophily) and one genotype is negatively correlated (heterophily). A replication study in an independent sample from the Framingham Heart Study verifies that DRD2 exhibits significant homophily and that CYP2A6exhibits significant heterophily. These unique results show that homophily and heterophily obtain on a genetic (indeed, an allelic) level, which has implications for the study of population genetics and social behavior. In particular, the results suggest that association tests should include friends’ genes and that theories of evolution should take into account the fact that humans might, in some sense, be metagenomic with respect to the humans around them.
PNAS February 1, 2011 vol. 108 no. 5 1993-1997
Correlated genotypes in friendship networks
+Author Affiliations
- Edited by Gene E. Robinson, University of Illinois, Urbana, IL, and approved December 15, 2010 (received for review August 6, 2010)
Abstract
It is well known that humans tend to associate with other humans who have similar characteristics, but it is unclear whether this tendency has consequences for the distribution of genotypes in a population. Although geneticists have shown that populations tend to stratify genetically, this process results from geographic sorting or assortative mating, and it is unknown whether genotypes may be correlated as a consequence of nonreproductive associations or other processes. Here, we study six available genotypes from the National Longitudinal Study of Adolescent Health to test for genetic similarity between friends. Maps of the friendship networks show clustering of genotypes and, after we apply strict controls for population stratification, the results show that one genotype is positively correlated (homophily) and one genotype is negatively correlated (heterophily). A replication study in an independent sample from the Framingham Heart Study verifies that DRD2 exhibits significant homophily and that CYP2A6exhibits significant heterophily. These unique results show that homophily and heterophily obtain on a genetic (indeed, an allelic) level, which has implications for the study of population genetics and social behavior. In particular, the results suggest that association tests should include friends’ genes and that theories of evolution should take into account the fact that humans might, in some sense, be metagenomic with respect to the humans around them.
PNAS February 1, 2011 vol. 108 no. 5 1993-1997
PNAS February 1, 2011 vol. 108 no. 5 1993-1997
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