Thursday, December 10, 2009

A Horse is a Horse, of Course, of Course, Unless of Course Its a Talking Horse Talking About Climate Change

Revising the recent evolutionary history of equids using ancient DNA. 2009. L. Orlando, et al. PNAS, published online before print December 9, 2009.

Straight from the horse’s mouth – all palaeontological research must be linked to climate change to get grants.
A new study using DNA from equid bones from caves in Eurasia and South America reveal that the Cape zebra and an extinct giant species from South Africa were simply large variants of the modern Plains zebra. The Cape zebra weighed up to 400 kilograms and stood up to 150 centimetres at the shoulder blades.

"The Plains zebra group once included the famous extinct quagga, so our results confirm that this group was highly variable in both coat colour and size."
"Previous fossil records suggested this group was part of an ancient lineage from North America but the DNA showed these unusual forms were part of the modern radiation of equid species," Dr Orlando says.

A new species of ass was also detected on the Russian Plains and appears to be related to European fossils dating back more than 1.5 million years. Carbon dates on the bones reveal that this species was alive as recently as 50,000 years ago.

"Overall, the new genetic results suggest that we have under-estimated how much a single species can vary over time and space, and mistakenly assumed more diversity among extinct species of megafauna," Professor Cooper says.

"It also implies that the loss of species diversity that occurred during the megafaunal extinctions at the end of the last Ice Age may not have been as extensive as previously thought.

In contrast, ancient DNA studies have revealed that the loss of genetic diversity in many surviving species appears to have been extremely severe," Professor Cooper says. "This has serious implications for biodiversity and the future impacts of climate change." link