Show one complete lineage in evolution

Y chromosome Adam and mitochondrial Eve show reasonably close concordance of age according to several studies documented hereJust a moment...Both coalesce around 100-200,000 years ago.Gender behavior in terms of dispersal can have a big impact on population genetics for exampleMol Ecol. 2004 Jun;13(6):1607-12. Related Articles, LinksGenetic evidence for sex-biased dispersal in resident bottlenose dolphins (Tursiops aduncus).Moller LM, Beheregaray LB.Marine Mammal Research Group, Graduate School of the Environment, Macquarie University, Sydney, NSW, 2109, Australia. luciana.moller@gse.mq.edu.auIn most mammals males usually disperse before breeding, while females remain in their natal group or area. However, in odontocete cetaceans behavioural and/or genetic evidence from populations of four species indicate that both males and females remain in their natal group or site. For coastal resident bottlenose dolphins field data suggest that both sexes are philopatric to their natal site. Assignment tests and analyses of relatedness based on microsatellite markers were used to investigate this hypothesis in resident bottlenose dolphins, Tursiops aduncus, from two small coastal populations of southeastern Australia. Mean corrected assignment and mean relatedness were higher for resident females than for resident males. Only 8% of resident females had a lower probability than average of being born locally compared to 33% of resident males. Our genetic data contradict the hypothesis of bisexual philopatry to natal site and suggest that these bottlenose dolphins are not unusual amongst mammals, with females being the more philopatric and males the more dispersing sex.orEvolution Int J Org Evolution. 2003 Aug;57(8):1931-46. Related Articles, LinksDiversification of Sulawesi macaque monkeys: decoupled evolution of mitochondrial and autosomal DNA.Evans BJ, Supriatna J, Andayani N, Melnick DJ.Department of Ecology, Evolution and Environmental Biology and Center for Environmental Research and Conservation, 1200 Amsterdam Avenue, Columbia University, New York 10027, USA. bje5@columbia.eduIn macaque monkeys, females are philopatric and males are obligate dispersers. This social system is expected to differently affect evolution of genetic elements depending on their mode of inheritance. Because of this, the geographic structure of molecular variation may differ considerably in mitochondrial DNA (mtDNA) and in autosomal DNA (aDNA) in the same individuals, even though these genomes are partially co-inherited. On the Indonesian island of Sulawesi, macaque monkeys underwent an explosive diversification as a result of range fragmentation. Today, barriers to dispersal have receded and fertile hybrid individuals can be found at contact zones between parapatric species. In this study, we examine the impact of range fragmentation on Sulawesi macaque mtDNA and aDNA by comparing evolution, phylogeography, and population subdivision of each genome. Our results suggest that mtDNA is paraphyletic in some species, and that mtDNA phylogeography is largely consistent with a pattern of isolation by distance. Autosomal DNA, however, is suggestive of fragmentation, in that interspecific differentiation across most contact zones is significant but intraspecific differentiation between contact zones is not. Furthermore, in mtDNA, most molecular variation is partitioned between populations within species but in aDNA most variation is partitioned within populations. That mtDNA has a different geographic structure than aDNA (and morphology) in these primates is a probable consequence of (1) a high level of ancestral polymorphism in mtDNA, (2) differences between patterns of ancestral dispersal of matrilines and contemporary dispersal of males, and (3) the fact that female philopatry impedes gene flow of macaque mtDNA.

Did not realize it was not accessible without a subscription. Sorry about that. Yes, it is Y-Adam and mt-Eve for humans.Here are some excerpts:

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Now, after almost a decade of study, two international teams have found the genetic trail leading to Adam, and it points to the same time and place where mitochondrial Eve lived. Described this month at a symposium on human evolution at Cold Spring Harbor Laboratory in New York, the genetic trail is so clear that it allows researchers to compare the migration patterns of men and women tens of thousands of years ago (see sidebar). It even pinpoints the living men whose Y chromosomes most resemble Adam's: a few Ethiopians, Sudanese, and Khoisan people living in southern Africa, including groups once known as Hottentots and Bushmen.

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Haplotype 1A, defined by an A at a particular site, appears to be ancestral because the A is found in chimpanzees, and Hammer's team found that in humans, it occurs only in some Africans. "It's at the highest frequency in the Khoisan," he says--the same population fingered by Underhill's team. Although the ancient form of 1A persisted in some groups in Africa, it also underwent a change to a G (guanine) 150,000 to 200,000 years ago in one descendant of Adam's. Like the T in Underhill's site, this form was carried out of Africa when men moved away and replaced other males around the globe.

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Both sets of results bolster the so-called Out of Africa model of human origins. "We think that anything existing in Asian males was replaced by this," says Hammer. Underhill agrees: "I think this speaks persuasively for an Out of Africa origin for modern humans."

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It depends on the locus tested. Another issue is that the estimates have huge standard deviations. Here is a recent paper that actually points to a likely source of the observed discrepancy documented by some groups i.e. female effective pop size is larger than male i.e. more females reproduce than males.Mol Biol Evol. 2004 Aug 18 [Epub ahead of print] Related Articles, LinksGenetic Evidence for Unequal Effective Population Sizes of Human Females and Males.Wilder JA, Mobasher Z, Hammer MF.Division of Biotechnology, University of Arizona, Tucson, AZ 85721, USA; Department of EEB, University of Arizona, Tucson, AZ 85721, USA.The time to the most recent common ancestor (TMRCA) of the human mitochondria (mtDNA) is estimated to be older than that of the non-recombining portion of the Y chromosome (NRY). Surveys of variation in globally distributed humans typically result in mtDNA TMRCA values just under 200 thousand years (kya) while those for the NRY range between 46 and 110 kya. A favored hypothesis for this finding is that natural selection has acted on the NRY leading to a recent selective sweep. An alternate hypothesis is that sexbiased demographic processes are responsible. Here we re-examine the disparity between NRY and mtDNA TMRCAs using data collected from individual human populations--a sampling strategy that minimizes the confounding influence of population subdivision in global datasets. We survey variation at 782 bp of the mitochondrial cytochrome c oxidase subunit 3 gene as well as at 26.5 kb of non-coding DNA from the NRY in a sample of 25 Khoisan, 24 Mongolians, and 24 Papua New Guineans. Data from both loci in all populations are best described by a model of constant population size, with the exception of Mongolian mtDNA which appears to be experiencing rapid population growth. Taking these demographic models into account, we estimate the TMRCAs for each locus in each population. A pattern that is remarkably consistent across all three populations is an approximately two-fold deeper coalescence for mtDNA than for the NRY. The oldest TMRCAs are observed for the Khoisan (73.6 kya for the NRY and 176.5 kya for mtDNA) while those in the non-African populations are consistently lower (averaging 47.7 kya for the NRY and 92.8 kya for mtDNA). Our data do not suggest that differential natural selection is the cause of this difference in TMRCAs. Rather, these results are most consistent with a higher female effective population size.

Hi RAZD,
Here is one study that addresses your question..the full article may require a subscription or purchasing the article...or going to a university library.Cheers,
MJ Hered. 2001 Nov-Dec;92(6):475-80. Related Articles, LinksModern African ape populations as genetic and demographic models of the last common ancestor of humans, chimpanzees, and gorillas.Jensen-Seaman MI, Deinard AS, Kidd KK.Department of Anthropology, Yale University, P.O. Box 208277, New Haven, CT 06520-8277, USA.In order to fully understand human evolutionary history through the use of molecular data, it is essential to include our closest relatives as a comparison. We provide here estimates of nucleotide diversity and effective population size of modern African ape species using data from several independent noncoding nuclear loci, and use these estimates to make predictions about the nature of the ancestral population that eventually gave rise to the living species of African apes, including humans. Chimpanzees, bonobos, and gorillas possess two to three times more nucleotide diversity than modern humans. We hypothesize that the last common ancestor (LCA) of these species had an effective population size more similar to modern apes than modern humans. In addition, estimated dates for the divergence of the Homo, Pan, and Gorilla lineages suggest that the LCA may have had stronger geographic structuring to its mtDNA than its nuclear DNA, perhaps indicative of strong female philopatry or a dispersal system analogous to gorillas, where females disperse only short distances from their natal group. Synthesizing different classes of data, and the inferences drawn from them, allows us to predict some of the genetic and demographic properties of the LCA of humans, chimpanzees, and gorillas.

Hi RAZD,
It is fairly common among social mammals for differences in dispersal among males and females to occur. Elephant herds are composed of a dominant matriarch, her daughters and close female relatives, and young of both sexes. Males, when they reach reproductive age, are forced to leave the herd and wander alone or in groups. Thus, they have a greater chance of dispersing their genes more widely i.e. they will tend to mate with females of other herds (preventing inbreeding) whereas females in a herd will tend, over time, to be more genetically similar. Since mitochondrial DNA is passed from mother to offspring only in mammals, it is not surprising that the genetic picture over time will differ between mitochondrial DNA and a nuclear genes.
Elephants are not the only example as the references I posted show that the same thing can occur in primates.

Hi Andya,
Cool! I collaborated with one of Don Melnicks postdocs on an elephant project...it's a small world.
Cheers,
M