Tuesday, May 23, 2006

Human influence on biological speciation (NY Times)

This article (NY Times, may require registration) is interesting for many reasons. The main idea is to point out the influence that humans have on the evolution of other organism populations. The process of speciation seems to be moving towards hybridization and selection for intermediate traits for many organism populations. Classification issues will abound - a good biology "hook" for the idea of representing "differentiated" cognitive resource populations.

Friday, May 19, 2006

A whole new twist on "I Can't Quit You Baby"

Patterson et al have published a study in Nature (press release) indicating that the common ancestry of humans and chimpanzees is more complex than suggested by recent and historic data interpretation. The new study, which utilized a large number of high fidelity DNA sequence comparisons, presents data that suggests that the common ancestor population split once, came back together to form a hybrid population, and then diverged once again to form the modern human and the modern chimpanzee. DNA sequence similarities (particularly on the X chromosome) indicate that the first population break resulted in the modern chimp line, and that the hybrid population evolved into the modern human.

..."Don'tcha realize sweet baby? Woman I don't know... which way to go. Woman I can't quit you babe." (from "I Can't Quit You Baby", a blues song performed by a number of great artists)

Friday, May 5, 2006

A distal enhancer and an ultraconserved exon are derived from a novel retroposon : Nature

A distal enhancer and an ultraconserved exon are derived from a novel retroposon : Nature

In essence: DNA sequencing of all modern vertebrates shows that there are many regions that are always the same, whatever the organism. Enter the modern "coelacanth", an organism (recently thought to be extinct) that has changed very little (in multiple measures) in hundreds of millions of years. When comparing the DNA of the coelacanth with vertebrates (especially mammals), it is found that some of the highly conserved regions in vertebrate DNA act as transposons (sequences of DNA that frequently switch position within the genome) in the coelacanth. Researchers looked at the vertebrate function of one of these transposon sequences and found that it had positioned itself within an RNA processing gene, making it possible for the cell to have another alternative splicing pattern for that protein product (thereby altering the function of the protein).