All humans may be descended from just TWO people and a catastrophic event almost wiped out ALL species 100,000 years ago,study suggests, Daily Mail interview & source article


"All humans may be descended from just TWO people and a catastrophic event almost wiped out ALL species 100,000 years ago,study suggests."

Daily Mail interview with scientists:

A scientific study has prompted speculation that all modern humans could have descended from a solitary pair who lived 100,000 to 200,000 years ago.

Scientists surveyed the genetic 'bar codes' of five million animals - including humans - from 100,000 different species and the results have prompted speculation that we sprang from a single pair of adults after a catastrophic event almost wiped out the human race.

All humans may be descended from just TWO people and a catastrophic event almost wiped out ALL species 100,000 years ago,study suggests.

Stoeckle and Thaler, the scientists who headed the study, concluded that ninety percent of all animal species alive today come from parents that all began giving birth at roughly the same time, less than 250 thousand years ago - throwing into doubt the patterns of human evolution.

These bar codes, or snippets of DNA that reside outside the nuclei of living cells, suggest that it's not just people who could have come from a single pair of beings, but nine out of every 10 animal species, too

Research prompted speculation humans and animals sprang from single pair.

This conclusion is very surprising,' Thaler admitted, 'and I fought against it as hard as I could.' 

Genetic 'bar codes' of 100,000 animals from different species were surveyed

This may have happened after a catastrophic event after the last ice age

Google bard summary:

The article "Why should mitochondria define species?" by Stoeckle and Thaler argues that mitochondria should be used to define species. They make the following points:

  • Mitochondria are inherited only from the mother, so they are not subject to the same type of genetic recombination as nuclear DNA. This makes them less likely to be affected by natural selection, and therefore more likely to reflect the evolutionary history of a species.

  • Mitochondrial DNA is relatively small, which makes it easier to sequence and compare. This makes it a more practical tool for species identification than nuclear DNA.

  • Mitochondrial DNA is found in all living organisms, including bacteria and archaea. This makes it a more universal marker of species than other genetic markers, such as nuclear DNA.

Stoeckle and Thaler argue that using mitochondria to define species would have a number of advantages. First, it would make it easier to identify species, especially in cases where nuclear DNA is not available or is difficult to sequence. Second, it would provide a more consistent and objective way to define species, which would be helpful for taxonomy and conservation. Third, it would allow us to track the evolutionary history of species more accurately.

The use of mitochondria to define species is not without its critics. Some argue that mitochondria are not always passed down from mother to offspring, and that they can be affected by horizontal gene transfer. Others argue that there are other genetic markers that are better suited for species identification, such as nuclear DNA barcoding.

Despite these criticisms, the use of mitochondria to define species is becoming increasingly popular. This is due in part to the advantages that Stoeckle and Thaler have outlined, as well as the fact that mitochondrial DNA is relatively easy and inexpensive to sequence. As a result, it is likely that mitochondria will continue to play an important role in the study of species evolution.

Here are some additional thoughts on the article:

  • The authors make a strong case for using mitochondria to define species. Their arguments are well-reasoned and supported by evidence.

  • The use of mitochondria to define species has the potential to revolutionize the way we study and understand evolution. It could help us to better understand the relationships between different species, and to track the evolutionary history of life on Earth.

  • I am excited to see how the use of mitochondria to define species develops in the future. It has the potential to be a powerful tool for understanding the natural world.

Article snippets:

Why should mitochondria define species?

https://doi.org/10.1101/276717

More than a decade of DNA barcoding encompassing about five million specimens covering 100,000 animal species supports the generalization that mitochondrial DNA clusters largely overlap with species

What evolutionary mechanisms account for synonymous clusters being largely coincident with species?

The answer depends on whether variants are phenotypically neutral

Phenotypically neutral variants are only subject to demographic processes—drift, lineage sorting, genetic hitchhiking, and bottlenecks

Mitochondrial barcodes provide a commensurable way to compare modern humans to other animal species

Several convergent lines of evidence show that mitochondrial diversity in modern humans follows from sequence uniformity followed by the accumulation of largely neutral diversity during a population expansion that began approximately 100,000 years ago

A straightforward hypothesis is that the extant populations of almost all animal species have arrived at a similar result consequent to a similar process of expansion from mitochondrial uniformity within the last one to several hundred thousand years.

The tight clustering of barcodes within species and unfilled sequence space among them are key facts of animal life that evolutionary theory must explain

Barcodes are unique in being quantifiably commensurable across all animal species and almost always yielding the same single simple answer.

Either of two evolutionary mechanisms might account for the facts: a) species-specific selection, or b) demographic processes acting independently of phenotype.

Similar neutral variation of humans and other animals implies that the extant populations of most animal species have, like modern humans, recently passed through mitochondrial uniformity.

At its origin DNA barcoding made no claim of contributing to evolutionary theory.

the small fraction of the genome (about 5% of the mitochondrial genome and less than one millionth of the total organism’s genome

As of late 2016 there were close to five million COI barcodes between the GenBank and BOLD databases.

There is no longer any doubt that DNA barcodes are useful and practical


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