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Patterns of microchromosome organization remain highly conserved throughout avian evolution

O'Connor, R E; Kiazim, L; Skinner, B; Fonseka, G; Joseph, S; Jennings, R; Larkin, D M


R E O'Connor

L Kiazim

B Skinner

G Fonseka

S Joseph

R Jennings

D M Larkin


The structure and organization of a species genome at a karyotypic level, and in interphase nuclei, have broad functional significance. Although regular sized chromosomes are studied extensively in this regard, microchromosomes, which are present in many terrestrial vertebrates, remain poorly explored. Birds have more cytologically indistinguishable microchromosomes (~ 30 pairs) than other vertebrates; however, the degree to which genome organization patterns at a karyotypic and interphase level differ between species is unknown. In species where microchromosomes have fused to other chromosomes, they retain genomic features such as gene density and GC content; however, the extent to which they retain a central nuclear position has not been investigated. In studying 22 avian species from 10 orders, we established that, other than in species where microchromosomal fusion is obvious (Falconiformes and Psittaciformes), there was no evidence of microchromosomal rearrangement, suggesting an evolutionarily stable avian genome (karyotypic) organization. Moreover, in species where microchromosomal fusion has occurred, they retain a central nuclear location, suggesting that the nuclear position of microchromosomes is a function of their genomic features rather than their physical size.


O'Connor, R. E., Kiazim, L., Skinner, B., Fonseka, G., Joseph, S., Jennings, R., & Larkin, D. M. (2018). Patterns of microchromosome organization remain highly conserved throughout avian evolution. Chromosoma, 128(1), 21-29.

Journal Article Type Article
Acceptance Date Nov 5, 2018
Publication Date Nov 17, 2018
Deposit Date Dec 13, 2018
Publicly Available Date Dec 14, 2018
Journal Chromosoma
Print ISSN 0009-5915
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 128
Issue 1
Pages 21-29
Public URL


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