Originally published October 24 2005
Cornell researchers examine the increased rate of human evolution
by Mike Adams, the Health Ranger, NaturalNews Editor
Researchers from Cornell University, Celera Genomics and Celera Diagnostics believe that natural selection explains the rapid changes in human genetics in our latest phase of development as a species.
Nature, Cornell scientists analyzed 11,624 genes, comparing how genes vary not only among 39 humans but also between the humans and a chimpanzee, whose DNA is 99 percent identical to humans.
The study suggests that positive Darwinian natural selection -- in which some forms of a gene are favored because they increase the probability of survival or reproduction -- is responsible for the increased rate of evolution.
The Cornell/Celera team found that genes involved in immune function, sperm and egg production, sensory perception and transcription factors (proteins that control which genes are turned on or off) have been particularly affected by positive selection and show rapid evolution in the last 5 million years, when humans shared a common ancestor with chimps.
Likewise, the researchers found that approximately 13 percent of the genes that may vary show evidence of slightly deleterious or harmful mutations in human populations; these include genes involved in determining the basic structure of cells and muscles as well as genes that control traffic in and out of the cell.
These mutations are subject to weak negative selection, according to the study.
In general, negative selection eliminates from the population very harmful changes to proteins that kill or stop reproduction.
But mutations that have led to slightly deleterious versions of the gene -- mutations that may cause disease or only slightly reduce the average number of children left by those that carried the mutation -- can by chance become quite common in the population.
The chimpanzee sequence was then used to identify which form of the gene was the original ancestral form and which was the derived or new type.
The Cornell researchers became involved at the analysis stage in order to make predictions about what types of changes are most likely to be functionally important.
All content posted on this site is commentary or opinion and is protected under Free Speech. Truth Publishing LLC takes sole responsibility for all content. Truth Publishing sells no hard products and earns no money from the recommendation of products. NaturalNews.com is presented for educational and commentary purposes only and should not be construed as professional advice from any licensed practitioner. Truth Publishing assumes no responsibility for the use or misuse of this material. For the full terms of usage of this material, visit www.NaturalNews.com/terms.shtml