Despite looking the same, no two zebra finches are ever alike, and that is because whenever an offspring is produced, the genetic material is a novel combination of that from it’s mother and father. In addition, novel mutations arise during the process of creating eggs and sperm, and that provides variation which selection can act on, leading to evolution of new species over millions of years.

In our recent study, led by Djivan Prentout (and the team at Columbia University, New York) we studied the whole genome sequences of 80 individual zebra finches from our captive population in Sydney. The birds came from three generations, i.e. offspring, their parents, and grand-parents. This allowed us to examine the number of mutations that arose as DNA was copied from one generation to the next.

Germline mutation and meiotic recombination are fundamental genetic processes that give rise to genetic diversity and fuel evolution. Most of our knowledge about these processes stems from a handful of model organisms and studies in mammals. Here, we characterized properties of mutation and recombination in the zebra finch (Taeniopygia castanotis), which, like other birds, differs from mammals in several potentially salient respects, including its karyotype and the mechanism by which recombination is directed to the genome. By sequencing the genomes of three-generation pedigrees, we identified de novo mutations and recombination events (both crossovers and non-crossovers).

We identified a total of 202 do novo mutations and 1088 cross-overs (whereby novel combinations of chromosomes were produced in offspring.

Our analysis indicates that the sex-averaged mutation rate is comparable to those of mammals with similar generation times. Several aspects of recombination resolutions are also similar to those in mammals, notably the estimated ratio of crossovers to non-crossovers. Thus, our findings indicate that many aspects of mutation and recombination remain conserved over large phylogenetic distances

The study can be found here