Identifying Mazama gouazoubira (Artiodactyla; Cervidae) chromosomes involved in rearrangements induced by doxorubicin

Abstract

The process of karyotype evolution in Cervidae from a common ancestor (2n = 70, FN = 70) has been marked by complex chromosomal rearrangements. This ancestral karyotype has been retained by the current species Mazama gouazoubira (Fischer 1814), for which a chromosomal polymorphism (Robertsonian translocations and the presence of B chromosomes) has been described, presumably caused by a chromosome fragility. Thus, this study has identified doxorubicin-induced chromosome aberrations and mapped the regions involved in breaks, which may be related to the chromosome evolution process. G-banding pattern showed that 21 pairs of chromosomes presented chromosomal aberrations, 60% of the total chromosome number of the species M. gouazoubira. Among chromosomes that carry aberrations, the region where they were most frequently concentrated was distal relative to the centromere. These data suggest that certain chromosomal regions may be more susceptible to chromosome fragility and consequently could be involved in karyotype differentiation in species of the family Cervidae.

Intrapopulation Chromosomal Polymorphism in <b><i>Mazama gouazoubira</i></b> (Cetartiodactyla; Cervidae): The Emergence of a New Species?

“…These differences are consequences of chromosomal rearrangements such as X-autosomal fusion in M. americana and M. nemorivaga and a suggested pericentric inversion in M. gouazoubira . The X differences found in brocket deer could be directly related to the chromosomal fragility observed by Vargas-Munar et al [2010] and Tomazella et al [2017]. The tendency of rearrangements observed in Mazama involving the X chromosome agrees with X-autosomal rearrangements found in this work.…”

“…The chromosomes X, 4, 7 and 16 identified in the polymorphism of the Pantanal population have among the highest rates of chromosomal aberrations; their frequencies were 12.41, 9.65, 15.17, and 9.19%, respectively. The exception was chromosomal pair 21, which was not reported by Tomazella et al [2017] as having chromosomal aberrations, but this result may be due to difficulty in identifying this small chromosome. Neitzel [1987], Fontana and Rubini [1990], and Dementyeva et al [2010] considered the putative ancestral Cervidae X chromosome as acrocentric.…”

“…The most frequently observed chromosome aberrations in M. gouazoubira by Vargas-Munar et al [2010] and Tomazella et al [2017] were chromatid breaks and gaps. According to VargasMunar et al [2010], M. gouazoubira presents the highest rates of chromosomal aberrations induced by doxorubicin among some deer species (M. nana , M. americana , and Blastocerus dichotomus) .…”

“…In the genus Mazama , chromosomal fragility may facilitate chromosomal breaks and rearrangements and be closely related to intraspecific polymorphisms, chromosomal evolution, and formation of species in the genus following geographic isolation [Vargas-Munar et al, 2010;Tomazella et al, 2017]. The most frequently observed chromosome aberrations in M. gouazoubira by Vargas-Munar et al [2010] and Tomazella et al [2017] were chromatid breaks and gaps.…”

“…According to VargasMunar et al [2010], M. gouazoubira presents the highest rates of chromosomal aberrations induced by doxorubicin among some deer species (M. nana , M. americana , and Blastocerus dichotomus) . Tomazella et al [2017] identified the chromosomes carrying chromosomal aberrations induced by doxorubicin in M. gouazoubira , which could be more prone to chromosomal fragility. The chromosomes with highest frequencies of aberrations were the pairs 1, 2, 4, 5, 6, 7, 15, 16, and X.…”