Núcleo de Pesquisa e Conservação de Cervídeos, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista-NUPECCE/FCAV/UNESP, 14884-900 Jaboticabal, Brazil.
Laboratório de Dosagens Hormonais, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo-FMVZ/USP, 05508-270 São Paulo, Brazil.
Genes (Basel). 2021 Jan 26;12(2):165. doi: 10.3390/genes12020165.
Chromosomal polymorphism plays a major role in speciation processes in mammals with high rates of karyotypic evolution, as observed in the family Cervidae. One remarkable example is the genus that comprises wide inter- and intra-specific chromosomal variability. To evaluate the impact of chromosomal polymorphisms as reproductive barriers within the genus , inter-specific hybrids between and (MGO × MNE) and intra-specific hybrids between cytotypes of (MAM) differing by a tandem (TF) or centric fusion (Robertsonian translocations-RT) were evaluated. MGO × MNE hybrid fertility was evaluated by the seminal quality and testicular histology. MAM hybrids estimation of the meiotic segregation products was performed by sperm-FISH analysis. MGO × MNE hybrids analyses showed different degrees of fertility reduction, from severe subfertility to complete sterility. Regarding MAM, RT, and TF carriers showed a mean value for alternate segregation rate of 97.74%, and 67.23%, and adjacent segregation rate of 1.80%, and 29.07%, respectively. Our results suggested an efficient post-zygotic barrier represented by severe fertility reduction for MGO × MNE and MAM with heterozygous TF. Nevertheless, RT did not show a severe effect on the reproductive fitness in MAM. Our data support the validity of MGO and MNE as different species and reveals cryptic species within MAM.
染色体多态性在具有高核型进化率的哺乳动物的物种形成过程中起着重要作用，如在鹿科中观察到的那样。一个显著的例子是属，它包含广泛的种间和种内染色体变异性。为了评估染色体多态性作为属内生殖障碍的影响，在和（MGO×MNE）种间杂交和（MAM）种内杂交之间进行了评估，种内杂交的核型差异为串联（TF）或着丝粒融合（罗伯逊易位-RT）。通过精液质量和睾丸组织学评估 MGO×MNE 杂种的可育性。通过精子-FISH 分析评估 MAM 杂种减数分裂分离产物的估计。MGO×MNE 杂种分析显示出不同程度的生育力降低，从严重的不育到完全不育。关于 MAM，RT 和 TF 携带者的交替分离率分别为 97.74%和 67.23%，相邻分离率分别为 1.80%和 29.07%。我们的结果表明，MGO×MNE 和 MAM 中的异质 TF 具有严重的生育力降低，这代表了一种有效的合子后障碍。然而，RT 在 MAM 的生殖适应性方面并没有表现出严重的影响。我们的数据支持了 MGO 和 MNE 作为不同物种的有效性，并揭示了 MAM 中的隐种。
