Reconstruction of gross avian genome structure, organization and evolution suggests that the chicken lineage most closely resembles the dinosaur avian ancestor

Romanov, M., Farré, M., Lithgow, P., Fowler, K., Skinner, B., O'Connor, R., Fonseka, G., Backström, N., Matsuda, Y., Nishida, C., Houde, P., Jarvis, E., Hanson, E., Burt, D., Larkin, D. and Griffin, D. (2014) Reconstruction of gross avian genome structure, organization and evolution suggests that the chicken lineage most closely resembles the dinosaur avian ancestor. BMC Genomics, 15 (1060). ISSN 1471-2164.

[img]
Preview
PDF
Fowler_Chicken_Lineage.pdf

Download (1MB)

Abstract

Background
The availability of multiple avian genome sequence assemblies greatly improves our ability to define overall genome organization and reconstruct evolutionary changes. In birds, this has previously been impeded by a near intractable karyotype and relied almost exclusively on comparative molecular cytogenetics of only the largest chromosomes. Here, novel whole genome sequence information from 21 avian genome sequences (most newly assembled) made available on an interactive browser (Evolution Highway) was analyzed.

Results
Focusing on the six best-assembled genomes allowed us to assemble a putative karyotype of the dinosaur ancestor for each chromosome. Reconstructing evolutionary events that led to each species' genome organization, we determined that the fastest rate of change occurred in the zebra finch and budgerigar, consistent with rapid speciation events in the Passeriformes and Psittaciformes. Intra- and interchromosomal changes were explained most parsimoniously by a series of inversions and translocations respectively, with breakpoint reuse being commonplace. Analyzing chicken and zebra finch, we found little evidence to support the hypothesis of an association of evolutionary breakpoint regions with recombination hotspots but some evidence to support the hypothesis that microchromosomes largely represent conserved blocks of synteny in the majority of the 21 species analyzed. All but one species showed the expected number of microchromosomal rearrangements predicted by the haploid chromosome count. Ostrich, however, appeared to retain an overall karyotype structure of 2n = 80 despite undergoing a large number (26) of hitherto un-described interchromosomal changes.

Conclusions
Results suggest that mechanisms exist to preserve a static overall avian karyotype/genomic structure, including the microchromosomes, with widespread interchromosomal change occurring rarely (e.g. in ostrich and budgerigar lineages). Of the species analyzed, the chicken lineage appeared to have undergone the fewest changes compared to the dinosaur ancestor.

Item Type: Article
Subjects: Q Science > Q Science (General) > Q0002 General
Divisions: Faculty of Social and Applied Sciences > School of Human and Life Sciences
Depositing User: Katie Fowler
Date Deposited: 18 Dec 2014 17:47
Last Modified: 21 Jan 2016 18:29
URI: https://create.canterbury.ac.uk/id/eprint/12977

Actions (login required)

Update Item (CReaTE staff only) Update Item (CReaTE staff only)

Downloads

Downloads per month over past year

View more statistics

Share

Connect with us

Last edited: 29/06/2016 12:23:00