I Envy JTEM wrote:
Primum Sapienti wrote:
I Envy JTEM wrote:
Primum Sapienti wrote:
DNA preserved in sediments
This is ld news, I've talked about it several times in the past, and
Jan 4th 2022 is old news?
I keep forgetting about your cognitive disability but, the "News" is very old.
In fact, I pointed out how I had talked about it in the past a number of times. So the "News" has to be old, else it could not have already been
dealt with.
How is it you can pretend to be capable of speaking on these topics when
you can't handle rudimentary communication skills?
You posting your ruminations does not constitute actual research.
This study examined distribution of DNA in the soil.
https://www.pnas.org/content/119/1/e2113666118
PNAS January 4, 2022
Significance
DNA preserved in sediments has emerged as an important source of
information about past ecosystems, independent of the discovery of skeletal remains. However, little is known about the sources of sediment DNA, the factors affecting its long-term preservation, and the extent to which it
may be
translocated after deposition. Here, we show that impregnated blocks of intact sediment are excellent archives of DNA. DNA distribution is highly heterogeneous at the microscale in the cave sediment we studied, suggesting that postdepositional movement of DNA is unlikely to be a common
phenomenon in cases where the stratigraphy is undisturbed. Combining micromorphological analysis with microstratigraphic retrieval of ancient DNA therefore allows genetic information to be associated with the detailed archaeological and ecological record preserved in sediments.
Abstract
Ancient DNA recovered from Pleistocene sediments represents a rich resource
for the study of past hominin and environmental diversity. However, little is known about how DNA is preserved in sediments and the extent to which it may
be translocated between archaeological strata. Here, we investigate DNA preservation in 47 blocks of resin-impregnated archaeological sediment collected
over the last four decades for micromorphological analyses at 13
prehistoric sites
in Europe, Asia, Africa, and North America and show that such blocks can preserve DNA of hominins and other mammals. Extensive microsampling of
sediment blocks from Denisova Cave in the Altai Mountains reveals that the taxonomic composition of mammalian DNA differs drastically at the millimeter-scale and that DNA is concentrated in small particles,
especially in
fragments of bone and feces (coprolites), suggesting that these are
substantial
sources of DNA in sediments. Three microsamples taken in close proximity in
one of the blocks yielded Neanderthal DNA from at least two male individuals closely related to Denisova 5, a Neanderthal toe bone previously recovered
from the same layer. Our work indicates that DNA can remain stably localized
in sediments over time and provides a means of linking genetic information to the archaeological and ecological records on a microstratigraphic scale.
"Our data suggest that hominin DNA in impregnated sediments is commonly localized rather than being distributed uniformly throughout the sediment matrix
and that a localized sample is more likely to yield DNA originating from a single
individual than is the case for loose sediment samples. Sampling of micromorphology blocks, therefore, offers the prospect of increasing the quantity
of aDNA that can be recovered from sediments, especially for hominins and
other
rare taxa."
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