How are gene duplications presereved, lost or changed during evolution? According to science magiazine they discuss the news story by using comparative analyses of nucleotide sequences for different eukaryotic species, found that the birthrate of new duplicates is high enough that every gene in a typical eukaryotic genonme can be expected to duplicate at least once in 500 million years. However, the half-life of a duplicate fene s imapratively short- only a few million years. Selective constraints on duplicate genes increase with time. The authors speculate that gene duplications my be important in the generation of new species.

JNANN

"How are gene duplications presereved, lost or changed during evolution?"

Probably in the same way that any mutation is. Through selective pressures. If the duplication provides and evolutionary advantage that makes an organism more likely to reproduce, even slightly, it will rapidly spread throughout the population.

"The authors speculate that gene duplications my be important in the generation of new species."

I would certainly agree with that. Most every major evolutionary step I guess came from gene duplications and the mutations on the duplications. Take for instance the first single cellular eukaryotic organism. These started to group together for adaptive reasons, and eventually started to specialize, then started to reproduce through the same mechanism. Making the first multicelular organism. All of these different 'types' of cells were variations on a single 'parent' type of cell. Once the organism hits the multicellular stage, different parts of it become specialized. It starts to evolve limbs and organs for specific functions. This is where gene duplication will play a big role. Once you have specific organs or limbs, the entire organ or limb can be easily duplicated when a gene gets duplicated. Snakes for instance are segmented animals. They have incerdibly complex segments repeated over and over again that change a little bit with each section. If a snake had a mutation that made it longer, all it would need to happen is for the gene that controls the number of segments to mutate and say 'make 8 segments' instead of 'make 7 segments' Biologists Richard Dawkins, one of my favorite authors, calls this a DC-10 mutation, after the process of adding additional 'segements' to DC-7 airplanes to make them a DC-10's. The same kind of mutation can turn a bilaterial symmetrical organism into a radially symetrical organism. Such a mutation could bring about huge advantageous, or vastly important bases for further mutations that can prove advantageous. People are often born with six fingers, this is a similiar kind of mutation in which a single gene or small groups of genes which dictates the number of fingers (notice it controls the number of fingers on BOTH hands AND toes on the feet, which indicates this feet and hands came from the same kind of mutation since a single gene or group of genes controls all of them) Instead of a massive mutation occuring that controls the placement of neves, bones, muscles, tissues, and everything else. A simple small mutation says 'make another one of those' This is where our first five digits came from. The individual traits of the digits can be controlled on thier own as well, notice our fingers are all different legnths. Bats have rediculously elongated fingers with memebranes stretched between them, and they have become wings. These kinds of mutations can lead to huge differences opening up organisms to take up niche environments and evolve along thier own evolutionary path, eventurally speciating. Very fascinating stuff.

Matus