Mucho más que un 1%: la verdadera cantidad de diferencias entre humanos y chimpancés

Este artículo trata de la diferencia del genoma de los humanos y de otras especies de primates. Este difiere en más de un 1%, lo que ha constituido una creencia común hasta este mismo año. En realidad, difieren hasta en un 10% y la naturaleza de estas diferencias es tal que bien podría haber sido la fuente más importante de novedad evolutiva y adaptación en nuestro linaj

Selection upon Genome Architecture: Conservation of Functional Neighborhoods with Changing Genes

An increasing number of evidences show that genes are not distributed randomly across eukaryotic chromosomes, but rather in functional neighborhoods. Nevertheless, the driving force that originated and maintains such neighborhoods is still a matter of controversy. We present the first detailed multispecies cartography of genome regions enriched in genes with related functions and study the evolutionary implications of such clustering. Our results indicate that the chromosomes of higher eukaryotic genomes contain up to 12% of genes arranged in functional neighborhoods, with a high level of gene co-expression, which are consistently distributed in phylogenies. Unexpectedly, neighborhoods with homologous functions are formed by different (non-orthologous) genes in different species. Actually, instead of being conserved, functional neighborhoods present a higher degree of synteny breaks than the genome average. This scenario is compatible with the existence of selective pressures optimizing the coordinated transcription of blocks of functionally related genes. If these neighborhoods were broken by chromosomal rearrangements, selection would favor further rearrangements reconstructing other neighborhoods of similar function. The picture arising from this study is a dynamic genomic landscape with a high level of functional organization