Galindo D J, Vozdova M, Kubickova S, Cernohorska H, Bernegossi A M, Kadlcikova D, Rubes J, Duarte J M B
Núcleo de Pesquisa e Conservação de Cervídeos, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista - NUPECCE/FCAV/UNESP, 14884-900, Jaboticabal, São Paulo, Brazil.
Central European Institute of Technology-Veterinary Research Institute, 621-00, Brno, Czech Republic.
Theriogenology. 2021 Jul 1;168:33-40. doi: 10.1016/j.theriogenology.2021.03.024. Epub 2021 Apr 2.
The genus Mazama stands out among the Neotropical deer due to their wide intra and interspecific karyotypic diversification, which is associated with an accentuated chromosomal fragility. There are reports of heterozygous Robertsonian translocation (RT) carriers in a free-range population of Mazama gouazoubira (brown brocket deer), as well as in captive animals of this and other species of the genus. To analyze possible negative impacts of heterozygous chromosome rearrangements on reproductive fitness of the carriers, we performed an analysis of sperm meiotic segregation in four brown brocket bucks, carriers of a rob(4;16), and compared the results with those of a normal buck. We established a reliable FISH and sperm-FISH protocol for the brown brocket deer using bovine (Bos taurus; diploid number, 2n = 60) whole chromosome painting (WCP) and BAC probes. Using BAC probes, we revealed the presence of a paracentric inversion (PAI) of the fused chromosome 4 in two of the four analyzed RT carriers. The mean frequency of normal/balanced sperm in the translocation carriers was significantly lower than in the normal buck (94.78% vs 98.40%). The mean value of total unbalanced spermatozoa was almost doubled in the RT/PAI carriers (6.68%) when compared to RT carriers (3.76%), but the difference was not statistically significant. This study demonstrated the efficiency of FISH with bovine WCP and BAC probes in the characterization of chromosome rearrangements and gametic segregation patterns in brown brocket deer. Our results indicate a low to moderate increase in the rates of unbalanced meiotic segregation products in brown brocket bucks heterozygous for RT and RT/PAIs.
麻羚属在新热带鹿类中格外突出，因为其种内和种间的核型多样化程度很高，这与染色体的显著脆弱性有关。有报道称，在自由放养的南美泽鹿（褐南美泽鹿）种群中存在杂合罗伯逊易位（RT）携带者，在该属的这种鹿以及其他物种的圈养动物中也有发现。为了分析杂合染色体重排对携带者生殖适应性可能产生的负面影响，我们对4只携带rob(4;16)的褐南美泽鹿雄鹿的精子减数分裂分离情况进行了分析，并将结果与一只正常雄鹿的结果进行了比较。我们利用牛（Bos taurus；二倍体数，2n = 60）全染色体涂染（WCP）和BAC探针，为褐南美泽鹿建立了可靠的荧光原位杂交（FISH）和精子荧光原位杂交（sperm-FISH）方案。使用BAC探针，我们在4只分析的RT携带者中的2只中发现了融合染色体4的臂内倒位（PAI）。易位携带者中正常/平衡精子的平均频率显著低于正常雄鹿（94.78%对98.40%）。与RT携带者（3.76%）相比，RT/PAI携带者中总不平衡精子的平均值几乎翻倍（6.68%），但差异无统计学意义。本研究证明了使用牛WCP和BAC探针进行FISH在表征褐南美泽鹿染色体重排和配子分离模式方面的有效性。我们的结果表明，对于杂合RT和RT/PAI的褐南美泽鹿雄鹿，减数分裂分离产生不平衡产物的比率有低到中等程度的增加。
