Results 1 to 3 of 3

Thread: Digging ancient signals out of modern human genomes

  1. #1
    Gold Member Class
    Posts
    2,781
    Sex
    Location
    Calne,England
    Ethnicity
    British and Irish
    Nationality
    Great Britain
    Y-DNA
    E-Y45878
    mtDNA
    H67

    United Kingdom Scotland England Ireland

    Digging ancient signals out of modern human genomes

    With new genome analysis tools, scientists have made significant advances in our understanding of modern humans' origins and ancient migrations.

    But trying to find ancient DNA, let alone prove that the ancient DNA is ancestral to a population living today is extremely challenging.

    A new study in Molecular Biology and Evolution (MBE) adds to this understanding by reconstructing artificial genomes with the analyses of the genome of 565 contemporary South Asian individuals to extract ancient signals that recapitulate the long history of human migration and admixture in the region.


    https://www.eurekalert.org/pub_relea...-das040219.php
    Please support Mental health research and world community grid

    Hidden Content
    Hidden Content
    Hidden Content
    Hidden Content

  2. The Following 9 Users Say Thank You to firemonkey For This Useful Post:

     Helen (04-06-2019),  JMcB (04-06-2019),  Judith (04-11-2019),  Nebuchadnezzar II (04-06-2019),  Nibelung (04-06-2019),  Piquerobi (04-06-2019),  poi (04-11-2019),  Reza (04-06-2019),  traject (04-06-2019)

  3. #2
    Registered Users
    Posts
    117
    Sex
    Ethnicity
    Kerala Syrian Christian
    Nationality
    Canadian
    Y-DNA
    L1a1b3a1a1
    mtDNA
    M6

    A couple of interesting notes from the paper:
    Although this could have been related to the lack of power of PCAdmix approach, Irula_S being free of any N component, based on qpAdm and D analyses, eliminates this possibility (notably Irula_S can be seen as a better representative of the South Asian component, since Paniya, the population used as source, shows 25% of West Eurasian affinity in qpAdm). qpGraph analyses based on a representative set of MASK_N and MASK_S populations, however, showed that both masked groups can be represented as un-admixed West Eurasian or South Asian populations, respectively (Supplementary Figure 9b-d). More in details, the MASK_S populations can be modelled through a tree with only minor influence from Onge (Supplementary Figure 9b), which still maintains few f4outliers, or through a slightly more complex tree (Supplementary Figure 9c) free from any outliers, in any case confirming the relatively homogeneous pre-admixture S substrate (also referred to as AASI by Narasimhan et al. (Narasimhan et al. 2018)) already highlighted by PCA
    We followed up these preliminary explorations and included N (represented by Gujaratis_N) and S (represented by Irula_S) within a more comprehensive qpGraph aimed at yielding the broader picture of involved ancestries. The obtained qpGraph (Figure 2) has no f2 or f4 outliers and shows S totrifurcate from East Asian and Andamanese groups (here represented by Han Chinese and Onge). Notably all alternative trees invoking earlier splits of East Asians or Andamanese yielded higher final scores and f4 outliers, pointing to the slightly early separation of S as the best possible trifurcation. Also, alternative models reverting the directionality of admixture between precursors of S and of Steppe_EMBA increased the number of f4 outliers.
    The masked Irula_S looks to be the best virtual genome to model AASI with and it'll be interesting to see how this variant looks in G25.
    Last edited by traject; 04-06-2019 at 01:13 PM.

  4. The Following 4 Users Say Thank You to traject For This Useful Post:

     Eihwaz (04-06-2019),  Helen (04-06-2019),  Megalophias (04-06-2019),  poi (04-11-2019)

  5. #3
    Registered Users
    Posts
    2,347
    Sex
    Y-DNA
    R1b-DF27 FGC17112
    mtDNA
    H5a1

    Quote Originally Posted by traject View Post
    A couple of interesting notes from the paper:



    The masked Irula_S looks to be the best virtual genome to model AASI with and it'll be interesting to see how this variant looks in G25.
    I pretty much showed that back in August.

    https://populationgenomics.blog/2018...t-south-asian/

  6. The Following 3 Users Say Thank You to Chad Rohlfsen For This Useful Post:

     etrusco (04-06-2019),  poi (04-11-2019),  traject (04-06-2019)

Similar Threads

  1. 137 ancient human genomes from across the Eurasian steppes
    By rozenfeld in forum Ancient (aDNA)
    Replies: 259
    Last Post: 08-31-2018, 07:30 PM
  2. Replies: 43
    Last Post: 06-10-2017, 05:12 PM
  3. Replies: 0
    Last Post: 03-18-2016, 09:08 PM
  4. Replies: 454
    Last Post: 02-09-2015, 02:24 AM
  5. Replies: 3
    Last Post: 08-10-2014, 06:20 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •