RonO
2024-09-11 22:09:24 UTC
Open Access
https://www.cell.com/cell-genomics/fulltext/S2666-979X(24)00177-0
https://www.livescience.com/archaeology/dna-of-thorin-one-of-the-last-neanderthals-finally-sequenced-revealing-inbreeding-and-50-000-years-of-genetic-isolation
They think that this Neanderthal male existed 42,000 years ago. This
would make him the most recent find in terms of geologic age. There is
some evidence that Neanderthals existed until around 30,000 years ago,
but we do not have fossil bones, just their tool set. Like other
Neanderthal individuals this one seems to be highly inbred and is the
product of close relatives mating. His sequence indicates that his
people separated from the other extant Neanderthal lineages around
50,000 years before this individual existed. Somehow this group of
Neanderthals remained isolated in their valley for a very long time.
They still retained the older Neanderthal tool set while their
contemporaries in Western Europe had adopted a new method of making tools.
It sort of looks like the population went the way of the Wrangle Island
Mammoths and inbreeding depression may have been one of factors involved
in their eventual demise.
The modern humans that invaded Europe seemed to have a means to limit
inbreeding. One sex stayed with the clan and the other left to join
other clans.
One thing about inbreeding is that it can mess with genetic relationship
analysis. Inbreeding causes loss of genetic variation in a population,
so you have to try to determine how much different the haplotypes are
from the those found in other populations, and try to separate the
genetic distance due to loss of variation the population once had, from
the variation that accumulated in the haplotypes that they still share
with the other populations. I do not know if this was done in this
case. Inbreeding sort of unzips a lineage and makes the branch length
to that individual look longer than it actually is, but the longer
branch length is due to the variation that has been lost, not gained.
Ron Okimoto
https://www.cell.com/cell-genomics/fulltext/S2666-979X(24)00177-0
https://www.livescience.com/archaeology/dna-of-thorin-one-of-the-last-neanderthals-finally-sequenced-revealing-inbreeding-and-50-000-years-of-genetic-isolation
They think that this Neanderthal male existed 42,000 years ago. This
would make him the most recent find in terms of geologic age. There is
some evidence that Neanderthals existed until around 30,000 years ago,
but we do not have fossil bones, just their tool set. Like other
Neanderthal individuals this one seems to be highly inbred and is the
product of close relatives mating. His sequence indicates that his
people separated from the other extant Neanderthal lineages around
50,000 years before this individual existed. Somehow this group of
Neanderthals remained isolated in their valley for a very long time.
They still retained the older Neanderthal tool set while their
contemporaries in Western Europe had adopted a new method of making tools.
It sort of looks like the population went the way of the Wrangle Island
Mammoths and inbreeding depression may have been one of factors involved
in their eventual demise.
The modern humans that invaded Europe seemed to have a means to limit
inbreeding. One sex stayed with the clan and the other left to join
other clans.
One thing about inbreeding is that it can mess with genetic relationship
analysis. Inbreeding causes loss of genetic variation in a population,
so you have to try to determine how much different the haplotypes are
from the those found in other populations, and try to separate the
genetic distance due to loss of variation the population once had, from
the variation that accumulated in the haplotypes that they still share
with the other populations. I do not know if this was done in this
case. Inbreeding sort of unzips a lineage and makes the branch length
to that individual look longer than it actually is, but the longer
branch length is due to the variation that has been lost, not gained.
Ron Okimoto