How genetic variation within a kind as well as loss of genetic info actually works...in other words some real science...point is-that the bears are still bears-just different genes switched on, off or lost...
And God made the beast of the earth after his kind.. Genesis 1:25
"Behe argues in Darwin Devolves on the topic.
He observes that studies of the polar bear genome reveal certain genes were under strong selection since these wonderful bears split from a common ancestor with black bears.
An article in the journal Cell by Liu et al. (2014) analyzed the genes that were “under stronger positive selection” in polar bears. This was done using algorithms that compare amino acid changes in those genes to other known homologous versions of the gene to predict whether the mutations were benign or “damaging” to each protein’s function. Behe looked at the results and wrote the following:
And God made the beast of the earth after his kind.. Genesis 1:25
"Behe argues in Darwin Devolves on the topic.
He observes that studies of the polar bear genome reveal certain genes were under strong selection since these wonderful bears split from a common ancestor with black bears.
An article in the journal Cell by Liu et al. (2014) analyzed the genes that were “under stronger positive selection” in polar bears. This was done using algorithms that compare amino acid changes in those genes to other known homologous versions of the gene to predict whether the mutations were benign or “damaging” to each protein’s function. Behe looked at the results and wrote the following:
The polar bear’s most strongly selected mutations — and thus the most important for its survival — occurred in a gene dubbed APOB, which is involved in fat metabolism in mammals.
That itself is not surprising, since the diet of polar bears
contains a very large proportion of fat
(much higher than in the diet of brown bears) from seal blubber,
so we might expect metabolic changes were needed to accommodate it.
But what precisely did the changes in polar bear APOB do to it compared to that of other mammals?
When the same gene is mutated in humans or mice,
studies show it frequently leads to high levels of cholesterol and heart disease. The scientists who studied the polar bear’s genome detected multiple mutations in APOB. Since few experiments can be done with grumpy polar bears, they analyzed the changes by computer. They determined that the mutations were very likely to be damaging — that is, likely to degrade or destroy the function of the protein that the gene codes for.
A second highly selected gene, LYST, is associated with
pigmentation, and changes in it are probably responsible for the blanching of the ancestors’ brown fur. Computer analysis of the multiple mutations of the gene showed that they too were almost certainly damaging to its function. In fact, of all the mutations in the seventeen genes that were most highly selected, about half were predicted to damage the function of the respective coded proteins. Furthermore, since most altered genes bore several mutations, only three to six (depending on the method of estimation) out of seventeen genes were free of degrading changes. Put differently, 65 to 83 percent of helpful, positively selected genes are estimated to have suffered at least one damaging mutation."
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