New research from the University of Kent suggests that chromosomes of the chicken and turkey lineage have undergone the fewest number of changes compared to their ancient avian ancestors, thought to be feathered dinosaurs. This research is part of a study by an international consortium of leading scientists who are looking into avian or bird genomes, that is, the complete set of genes from these creatures. Their genomes tell a story of how various birds evolved.
Professor Darren Griffin of the University of Kent led the team that found chickens and turkeys genetically closest to dinosaurs. Griffin said:
Bird genomes are distinctive in that they have more tiny microchromosomes than any other vertebrate group. These small packages of gene-rich material are thought to have been present in their dinosaur ancestors.
We found that the chicken has the most similar overall chromosome pattern to its avian dinosaur ancestor.
Birds – the living descendants of dinosaurs – have been thought for some time to have undergone a rapid burst of evolution after most dinosaur species were wiped out, over 60 million years ago.
The detailed family tree of modern birds, however, has confused biologists for centuries. Even today, the molecular details of how birds arrived at the spectacular biodiversity of more than 10,000 species is barely known.
This new research, which formed part of a vast study carried out over the past four years by the international Avian Phylogenomics Consortium – 200 scientists, 80 institutions, 20 countries – involved the analysis of the whole genome structure of the chicken, turkey, Pekin duck, zebra finch and budgerigar.
The research team studied data from a total of 21 avian genomes and one reptile species. The team focused on the six best-assembled genomes to put together a karyotype – an organized profile – of the dinosaur ancestor for each chromosome.
The researchers also found that the fastest rate of change had occurred in the zebra finch and budgerigar, consistent with more rapid speciation events in songbirds and their relatives.
Bottom line: Chickens and turkeys have experienced fewer gross genomic changes than other birds as they evolved from their dinosaur ancestor suggests new research from the University of Kent.