On Dead Things Gemma Tarlach comments on the final days of the woolly mammoth:
Source: BBC
The genome of the Wrangel mammoth, which lived in a population of about 300 animals, had numerous mutations compared with its distant mainland cousin. Accumulating mutations over time is not in itself an issue — it’s the way of evolution, man — but it does create problems when the mutations have a negative impact on gene expression and function. And that’s what happened with the Wrangel animals.
According to the research, published today in PLOS Genetics, the pile-up of deleterious mutations left the Wrangel mammoth without a significant number of olfactory receptors, reducing its ability to pick up scents. The Wrangel woollies also lost a number of urinary proteins. In related species, such as the Indian elephant, these proteins are part of the language of social interaction and mate selection.
It also appears that mutations to genes controlling fur texture led to a satiny coat. Because typically stiff mammoth hairs evolved to offer some protection from the harsh Arctic elements, the satin stylings of the Wrangel herd may have made it harder for the animals to survive.
The accumulation of these and other mutations led to what the researchers describe as a “genomic meltdown.” The new evidence supports what are known as nearly neutral theories of genome evolution, which hold that harmful mutations can accumulate in small populations. Essentially: inbreeding bad. It might sound obvious, but this woolly mammoth study represents a rare chance for researchers to make direct comparisons between genomes from markedly different population sizes within a species.
I know some readers will scoff that this tells us nothing new. But thanks to the study, scientists have a better idea of how genomes change (and deteriorate) in small populations. This is important both for conservationists trying to save species with dwindling numbers and for de-extinction advocates who want to bring back departed flora and fauna — including the woolly mammoth.
And so passed one of the sexiest extinct beasties known to man – destined to be an object lesson.
