Chromosomal painting of the sandpiper (Actitis macularius) detects several fissions for the Scolopacidae family (Charadriiformes)

Abstract

Background: The Scolopacidae family (Suborder Scolopaci, Charadriiformes) is composed of sandpipers and snipes; these birds are long-distance migrants that show great diversity in their behavior and habitat use. Cytogenetic studies in the Scolopacidae family show the highest diploid numbers for order Charadriiformes. This work analyzes for the first time the karyotype of Actitis macularius by classic cytogenetics and chromosome painting. Results: The species has a diploid number of 92, composed mostly of telocentric pairs. This high 2n is greater than the proposed 80 for the avian ancestral putative karyotype, suggesting that fission rearrangements have formed smaller macrochromosomes and microchromosomes. Fluorescence In Situ Hybridization using Burhinus oedicnemus whole chromosome probes confirmed these fissions in all pairs of macrochromosomes. Conclusion: Comparative analysis with other species of Charadriiformes studied by chromosome painting together with the molecular phylogenies for the order allowed us to raise hypotheses about the chromosomal evolution in suborder Scolopaci. From this, we can establish a clear idea of ​​how chromosomal evolution occurred in this suborder.

Genome stability is in the eye of the beholder: recent retrotransposon activity varies significantly across avian diversity

“…While early comparisons of avian genomes were restricted to the chicken and zebra finch, where high level comparisons of synteny and karyotype led to the conclusion that bird genomes were largely stable compared to mammals (Ellegren 2010), the discovery of many intrachromosomal rearrangements across birds (Hooper and Price 2017;Skinner and Griffin 2012;Zhang et al 2014;Farre et al 2016) and interchromosomal recombination in falcons, parrots and sandpipers (O'Connor et al 2018;Coelho et al 2019;Pinheiro et al 2021) has shown that at a finer resolution for comparison, the avian genome is rather dynamic. The highly variable rate of TE expansion we have observed across birds extends knowledge from avian orders with "unusual" repeat landscapes, i.e., Piciformes (Manthey et al 2018) and Passeriformes (Warren et al 2010), and provides further evidence that the genome evolution of bird orders and species within orders differs significantly, even though synteny is often conserved.…”