How the Signature of Evolution is Written into Your Genome

Comparison of similar genetic sequencesPhoto: Chen et al. 2010

Published just this week in the peer-reviewed open access journal PLoS One was a paper entitled Universal Global Imprints of Genome Growth and Evolution – Equivalent Length and Cumulative Mutation Density.

The Taiwanese researchers reviewed the genomes of humans and several other organisms looking for examples of past genetic duplications.

Essentially, genetic mutations often duplicate segments of genes; this is known as gene duplication. At first, these duplications often have no function. Eventually genetic mutations then continue to mutate these duplicated segments further; thus, they become new, additional pieces of genetic information which can eventually describe something completely novel in the organism.

Scientists are pretty sure this method of “Duplicate and change” is one of the driving evolutionary forces which creates new, interesting genetic information (Ohno 1967).

This powerful combination of mutational forces has also been actually observed in nature. Two specific cases include examples in Langur monkeys and yeast.

The scientists behind this recent paper applied several bioinformatic models in order to locate examples of such duplicated sequences. Throughout our extensive past evolutionary history, humans have stockpiled a large number of duplications which have since mutated further. Most of these duplicated sequences have had millions of years to genetically diverge from their original copies, and thus locating them can be tricky.

Average length of Duplicated Sequences per chromosomePhoto: Chen et al. 2010

The researchers found large numbers of these duplicated segments throughout the genomes of several organisms, including humans. Not only that, but models confirmed that these sites were indeed characterized by segment duplication and point mutations. This powerful “imprint” of such primitive natural forces in our genome not only assists in again confirming the basic principles of natural selection, but gives scientists serious insight into exactly how life on Earth has evolved during the last 3.5 billion years.

Cited sources of interest:

Chen H-D, Fan W-L, Kong S-G, Lee H-C (2010) Universal Global Imprints of Genome Growth and Evolution – Equivalent Length and Cumulative Mutation Density. PLoS ONE 5(4): e9844. doi:10.1371/journal.pone.0009844

Ohno, S. (1967). Sex Chromosomes and Sex-linked Genes. Springer-Verlag. ISBN 91-554-5776-2.