School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK.
Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London NW1 0T, UK.
Cells. 2021 Feb 9;10(2):362. doi: 10.3390/cells10020362.
Avian genomes typically consist of ~10 pairs of macro- and ~30 pairs of microchromosomes. While inter-chromosomally, a pattern emerges of very little change (with notable exceptions) throughout evolution, intrachromosomal changes remain relatively poorly studied. To rectify this, here we use a pan-avian universally hybridising set of 74 chicken bacterial artificial chromosome (BAC) probes on the macrochromosomes of eight bird species: common blackbird, Atlantic canary, Eurasian woodcock, helmeted guinea fowl, houbara bustard, mallard duck, and rock dove. A combination of molecular cytogenetic, bioinformatics, and mathematical analyses allowed the building of comparative cytogenetic maps, reconstruction of a putative Neognathae ancestor, and assessment of chromosome rearrangement patterns and phylogenetic relationships in the studied neognath lineages. We observe that, as with our previous studies, chicken appears to have the karyotype most similar to the ancestor; however, previous reports of an increased rate of intrachromosomal change in Passeriformes (songbirds) appear not to be the case in our dataset. The use of this universally hybridizing probe set is applicable not only for the re-tracing of avian karyotype evolution but, potentially, for reconstructing genome assemblies.
禽类基因组通常由约 10 对大染色体和约 30 对小染色体组成。虽然在染色体间，进化过程中出现了几乎没有变化的模式（有一些显著的例外），但染色体内部的变化仍然相对研究较少。为了解决这个问题，我们在这里使用了一组泛禽类普遍杂交的 74 个鸡细菌人工染色体（BAC）探针，用于研究 8 种鸟类的大染色体：普通乌鸦、大西洋金丝雀、欧亚红尾鸲、盔鸡、侯伯鸨、绿头鸭和岩鸽。分子细胞遗传学、生物信息学和数学分析的结合，使得构建比较细胞遗传学图谱、重建假定的新颌类祖先以及评估研究的新颌类谱系中的染色体重排模式和系统发育关系成为可能。我们观察到，与我们之前的研究一样，鸡似乎具有与祖先最相似的染色体组型；然而，以前关于雀形目（鸣禽）中染色体内部变化率增加的报告在我们的数据集里似乎并非如此。这种普遍杂交探针集的使用不仅适用于追溯鸟类染色体组进化，还可能适用于重建基因组组装。
