Standard karyotype of the domestic horse (Equus caballus)

Abstract

The following decisions concerning the banded karyotype of the horse (Equus caballus) were made at the second International conference for Standardization of Domestic Animal Karyotypes, held at Jouy-en Josas, France, 22nd-26th May 1989: (1) numbering of the chromosomes was modified to correspond to an arrangement into only two groups (the non-acrocentrics and the acrocentrics) within which the autosomes are placed according to length alone; (2) a more compact karyotype arrangement was adopted: chromosomes 1 to 5 on the first row, 6 to 10 on the second, 11 to 13, and, at the far right, X and Y on the third row, 14 to 19 on the fourth row, chromosomes 20 to 25 on the fifth, and 26 to 31 on the sixth row; (3) the NOR-bearing horse chromosomes were identified as numbers 1, 28 and 31.

Sister chromatid exchange in selected horse breeds (<i>Equus caballus</i>)

“…The 32nd pair are sex chromosomes. Chromosome X is one of the largest chromosomes in the karyotype, while chromosome Y is one of the smallest (Richer et al 1990, Bowling et al 1997, Wade et al 2009). …”

Cytogenetic Characterization of Brazil Origin Marajoara Horses

“…Richer et al, (1990). However, chromosomal biometry results in this work diverged from the division of karyotype into acrocentric and non-acrocentric groups, as suggested by Richer et al, (1990), since this kind of morphology is not present in the karyotype.…”

“…Richer et al, (1990). However, chromosomal biometry results in this work diverged from the division of karyotype into acrocentric and non-acrocentric groups, as suggested by Richer et al, (1990), since this kind of morphology is not present in the karyotype. In our bibliographical survey, we observed that publications relating to the chromosomal characterization of E. caballus did not present a morphological description of each chromosome pair.…”

“…The representative metaphases were selected and photographed to assemble the individual karyotype following standards for domestic horses, according to Richer et al, (1990). In addition, it was estimated the centromeric index CI (ration between short arm and total length of the chromosome), using the software Micro Measure (version 3.3 by Colorado State University) from five different animals karyotypes.…”

“…This was followed by countless studies on various breeds of the specie aiming the chromosomal characterization and establishing of C, G and NOR band patterns by Buckland et al, (1976), Kopp et al, (1981), Lui et al (1990), Richer et al, (1990) and Slota et al, (2007). However, studies about the karyotypic of Marajoara breed are unknown.…”