Finally, we examined how changes in recombination rates in hybrids correspond to patterns of gene flow and differentiation, as an extension of how inverted regions (which have low recombination in hybrids) often bear high divergence between species.
Mice models of inflammation have more and more been shown to bear a grave divergence from human immune processes.
Within the remaining ursine bears, the estimated divergence times all show overlapping confidence intervals, except for those within the brown bear clade.
The TF-motif divergence bears similarity to earlier comparison strategies (Roepcke et al, 2005; Mahony and Benos, 2007) in the use of KL divergence but as far as we know, taking the minimum is a novel feature.
We found evidence in the mitochondrial and/or nuclear genomes for accelerated evolutionary rates, positive selection, and functional divergence in bears, with particularly strong signals in the polar bear lineage.
The initial divergence within bears occurred between the giant panda and all remaining bears, estimated to have happened between 17.9 and 22.1 Ma (range of posterior means across analyses).
The age of the MRCA of polar bears (node D) is estimated at 43 kyr BP (95% HPD 19 73 kyr BP), and the divergence between polar bears and ABC islands bears (node F) is estimated to have occurred about 58 kyr BP (95% HPD: 48 72 kyr BP).
Results here suggest that the mitochondrial COXIII and ND4 genes exhibit some evidence for both positive selection and functional divergence in bears (but not other carnivores), which may be suggestive of molecular adaptation.
The minimum for the divergence of bears and seals was set to 33.9 Ma, based on the fossil species Parictis montanus [ 66] and Parictis parvus [ 67] both dated to 38 33.9 Ma, and the first well-described members on the bear lineage.
This hybridization is likely an underlying cause of the discordance between the mitochondrial and nuclear phylogenetic trees, with the time since divergence of polar bears and ABC brown bears being much shorter for mitochondrial DNA than nuclear DNA.
