Y chromosome

General discussions regarding DNA and its uses in genealogy research

Posts: 3266
Joined: Fri Mar 16, 2012 5:43 pm

MtDNA:
U5b2b
PostPosted: Thu Jul 01, 2021 4:34 pm
https://www.pnas.org/content/117/42/26273
Dynamic evolution of great ape Y chromosomes
View ORCID ProfileMonika Cechova, View ORCID ProfileRahulsimham Vegesna, View ORCID ProfileMarta Tomaszkiewicz, View ORCID ProfileRobert S. Harris, Di Chen, Samarth Rangavittal, Paul Medvedev, and View ORCID ProfileKateryna D. Makova.

"Among great apes, the Y has so far been assembled only in human (6), chimpanzee (7), and gorilla (8). A comparative study of these Y assemblies (8) uncovered some unexpected patterns which could not be explained with the data from three species alone. Despite a recent divergence of these species (∼7 million years ago [MYA]) (9), their Y chromosomes differ enormously in size and gene content, in sharp contrast to the stability of the rest of the genome. For example, the chimpanzee Y is only half the size of the human Y, and the percentage of gene families shared by these two chromosomes (68%) that split ∼6 MYA (9) is similar to that shared by human and chicken autosomes that split ∼310 MYA (7). Puzzlingly, in terms of shared genes and overall architecture, the human Y is more similar to the gorilla Y than to the chimpanzee Y even though human and chimpanzee have a more recent common ancestor (8). Y chromosomes from additional great ape species should be sequenced to understand whether high interspecific variability in gene content and architecture is characteristic of all great ape Ys."

Also
The evolutionary history of Neanderthal and Denisovan Y chromosomes
View ORCID ProfileMartin Petr1,*, View ORCID ProfileMateja Hajdinjak1,2, View ORCID ProfileQiaomei Fu3,4,5, Elena Essel1, View ORCID ProfileHélène Rougier6, View ORCID ProfileIsabelle Crevecoeur7, View ORCID ProfilePatrick Semal8, Liubov V. Golovanova9, Vladimir B. Doronichev9, View ORCID ProfileCarles Lalueza-Fox10, View ORCID ProfileMarco de la Rasilla11, View ORCID ProfileAntonio Rosas12, Michael V. Shunkov13, View ORCID ProfileMaxim B. Kozlikin13, View ORCID ProfileAnatoli P. Derevianko13, View ORCID ProfileBenjamin Vernot1, View ORCID ProfileMatthias Meyer1, View ORCID ProfileJanet Kelso1,*

Abstract
"Ancient DNA has provided new insights into many aspects of human history. However, we lack comprehensive studies of the Y chromosomes of Denisovans and Neanderthals because the majority of specimens that have been sequenced to sufficient coverage are female. Sequencing Y chromosomes from two Denisovans and three Neanderthals shows that the Y chromosomes of Denisovans split around 700 thousand years ago from a lineage shared by Neanderthals and modern human Y chromosomes, which diverged from each other around 370 thousand years ago. The phylogenetic relationships of archaic and modern human Y chromosomes differ from the population relationships inferred from the autosomal genomes and mirror mitochondrial DNA phylogenies, indicating replacement of both the mitochondrial and Y chromosomal gene pools in late Neanderthals. This replacement is plausible if the low effective population size of Neanderthals resulted in an increased genetic load in Neanderthals relative to modern humans."

Posts: 3266
Joined: Fri Mar 16, 2012 5:43 pm

MtDNA:
U5b2b
PostPosted: Tue Aug 03, 2021 7:51 am
The scientists are suggesting that the Neanderthals originated in Africa 300,000 ybp? Making it all fit.

https://www.science20.com/news_staff/ne ... _confirmed

"The findings wouldn't add much, they didn't do original work, except it has been assumed that Neanderthals were all type O, the way chimpanzees are all type A and gorillas all type B but the new paper showed these ancient hominins already displayed the full range of ABO variability observed in modern humans. Extensive analysis covering other blood group systems turned up alleles that argue in favour of African origins for Neanderthals and Denisovans."

Another new paper.
Human origins in Southern African palaeo-wetlands? Strong claims from weak evidence.

https://www.sciencedirect.com/science/a ... 0321000443

Abstract
"Attempts to identify a ‘homeland’ for our species from genetic data are widespread in the academic literature. However, even when putting aside the question of whether a ‘homeland’ is a useful concept, there are a number of inferential pitfalls in attempting to identify the geographic origin of a species from contemporary patterns of genetic variation. These include making strong claims from weakly informative data, treating genetic lineages as representative of populations, assuming a high degree of regional population continuity over hundreds of thousands of years, and using circumstantial observations as corroborating evidence without considering alternative hypotheses on an equal footing, or formally evaluating any hypothesis. In this commentary we review the recent publication that claims to pinpoint the origins of ‘modern humans’ to a very specific region in Africa (Chan et al., 2019), demonstrate how it fell into these inferential pitfalls, and discuss how this can be avoided."

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