Just a short update regarding progress on the book. I am deciding on a cover design while addressing suggested changes as they come back from the editor, and preparing marketing material. If all goes to plan, I am on track for a March publication date–thanks to your support.
In the early 1960s paleontologist Bjorn Kurtén thought that polar bears likely arose from a brown bear ancestor based on fossil evidence alone, and his estimate of when this happened was determined by the age of fossil remains of both species. As I will show in the chapters that follow, despite more fossil evidence being available and additional evidence from molecular genetic studies, his estimate is still the most likely time frame for when the polar bear came to be.
Two scientific papers in June on polar bear evolution got a bit of media attention but not what the topic deserves. I’ve not written about them because I am currently working on a larger piece putting this conflicting genetic information into full context. Have patience, it’s coming.
A couple weeks ago I had a fabulous chat with Daniel Vitalis from Wildfed about a wide range of topics, including my work on polar bears and domestication as a process of speciation. The podcast went live this morning – have a listen here (also copied below), I think you’ll enjoy it. One hour, 36 minutes.
The latest addition to the never-ending story of when-and-why polar bear evolution took place according to geneticists (Liu et al. 2014 — the 8th such paper in less than 4 years, if you can believe it) is getting way, way more media attention than it deserves.
Liu et al. 2014 figure provided in the abstract.
This multi-member research team used a new data set (mostly Scandinavian brown bears and Greenland polar bears, for a change) to add not much of anything new on the evolutionary insight front except yet another estimate of when polar bears came to be.1
However, the real focus of the paper is the description of their finding of a few genetic differences between brown bears and polar bears that they identified. They found a few genes in polar bears were different than brown bears and made a boat load of assumptions about what these might mean.
Their discovery was not accompanied by any attempt to demonstrate that the changes in gene architecture they found also involved a change in the function of the genes or were associated with different effects on bear physiology. If a changed gene cannot be shown to act differently or to have a demonstrated new physiological effect on the animal in question, the changes themselves mean next to nothing – especially for evolution!
That’s my take – see what you think. It looks long but a lot of it is quotes.
Posted in Evolution
Tagged adaptation, age of polar bears, APOB gene, blubber, brown bear, evolution, fat genes, genetic divergence, genetics, high-fat diet, Liu, polar bear, speciation, UC Berkeley, when polar bears arose
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