Analysis of the genomes of different mammals has shown that, although they all have a similar catalogue of genes, they may be ordered differently and turned on and off differently. These chromosomal rearrangements influence gene function and regulation and contribute to defining the identity of species, but their origin was unknown until now.
A study led by the Autonomous University of Barcelona (UAB) and the University of Kent (United Kingdom) shows that the formation of male germ cells is key to determining which regions of the genome are reorganized within and between chromosomes during evolution.
“The main objective of this study is to understand the origin of the biodiversity surrounding us. All the species that inhabit the planet share genes, which can be arranged differently in each species, in the form of chromosomes”, explains Aurora Ruiz-Herrera, a researcher at the UAB Institute of Biotechnology and Biomedicine (IBB).
In nature, the diversity of species that we find is also reflected in a different number of chromosomes. Humans, for example, have 46 chromosomes, but the mouse has 40 and the rhinoceros are characterized by 86 chromosomes. So there is a wide variety of ways in which the genome can be packaged inside cells. As all mammals share a common ancestor, during the evolution of the species there have been rearrangements of specific genes in each taxonomic group that can expose the diversity in number and structure of the chromosomes that we detect today in current species. These rearrangements take place in the germline – during the formation of eggs and sperm – so that they can be passed on to the next generations, to the offspring. Specifically, they are associated with specific physical and biochemical processes in the final stages of male gamete production, once meiotic cell divisions are complete.
This study has been published in Nature Communications.