Extensive Homology of Chicken Macrochromosomes in the Karyotypes of <b><i>Trachemys scripta elegans</i></b> and <b><i>Crocodylus niloticus</i></b> Revealed by Chromosome Painting despite Long Divergence Times

Abstract

We report extensive chromosome homology revealed by chromosome painting between chicken (Gallus gallus domesticus, GGA, 2n = 78) macrochromosomes (representing 70% of the chicken genome) and the chromosomes of a turtle, the red-eared slider (Trachemys scripta elegans, TSC, 2n = 50), and the Nile crocodile (Crocodylus niloticus, CNI, 2n = 32). Our data show that GGA1–8 arms seem to be conserved in the arms of TSC chromosomes, GGA1–2 arms are separated and homologous to CNI1p, 3q, 4q and 5q. In addition to GGAZ homologues in our previous study, large-scale GGA autosome syntenies have been conserved in turtle and crocodile despite hundreds of millions of years divergence time. Based on phylogenetic hypotheses that crocodiles diverged after the divergence of birds and turtles, our results in CNI suggest that GGA1–2 and TSC1–2 represent the ancestral state and that chromosome fissions followed by fusions have been the mechanisms responsible for the reduction of chromosome number in crocodiles.

First Description of the Karyotype and Sex Chromosomes in the Komodo Dragon <b><i>(Varanus komodoensis)</i></b>

“…Srikulnath et al [2013] investigated rearrangements in 2 species of monitor lizards using comparative gene mapping and came to the same conclusion as King and King [1975] that the rearrangement of macrochromosomes is predominantly caused by pericentric inversions and centromere repositioning rather than interchromosomal changes. They also confirmed that the genome organisation at the chromosomal level of squamate reptiles is rather conserved as previously suggested by Pokorná et al [2011aPokorná et al [ , 2012 or Kasai et al [2012].…”

Isolating Chromosomes of the Komodo Dragon: New Tools for Comparative Mapping and Sequence Assembly

“…[ Norops ] sagrei ) [Giovannotti et al, 2017], 1 turtle, and 1 crocodile ( Trachemys scripta elegans , Crocodylus niloticus ) [Kasai et al, 2012a]. Similarly, chromosome-specific DNA was used to produce paints which were employed for cross-species chromosome painting experiments in several species of reptiles [Kasai et al, 2012b;Johnson Pokorná et al, 2015;Trifonov et al, 2015].…”

Los cromosomas de las tortugas tropicales: Kinosternon leucostomum, Trachemys scripta y Staurotypus triporcatus (Testudines: Kinosternidae/Emydidae)

“…El análisis citogenético de los cromosomas de T. scripta de Tabasco, ha presentado diferencias en la morfología y clasificación de los cromosomas en el complemento cariotípico con relación a otros estudios en Trachemys y otros taxones de la familia (Cleiton & Giuliano-Caetano, 2008;Martínez et al, 2009;Kasai et al, 2012).…”