Abstract:
Chromosomal rearrangements are often associated with playing a role in the speciation process. However, the underlying mechanism that favors the genetic isolation associated with chromosomal changes remains elusive. In this sense, the genus Mazama is recognized by its high level of karyotype diversity among species with similar morphology. A cryptic species complex has been identified within the genus, with the red brocket deer (Mazama americana and Mazama rufa) being the most impressive example. The chromosome variation was clustered in cytotypes with diploid numbers ranging from 42 to 53 and was correlated with geographical location. We conducted an analysis of chromosome evolution of the red brocket deer complex using comparative chromosome painting and Bacterial Artificial Chromosome (BAC) clones among different cytotypes. The aim was to deepen our understanding of the karyotypic relationships within the red brocket, thereby elucidating the significant chromosome variation among closely related species. This underscores the significance of chromosome changes as a key evolutionary process shaping their genomes. The results revealed the presence of three distinct cytogenetic lineages characterized by significant karyotypic divergence, suggesting the existence of efficient post-zygotic barriers. Tandem fusions constitute the main mechanism driving karyotype evolution, following a few centric fusions, inversion X-autosomal fusions. The BAC mapping has improved our comprehension of the karyotypic relationships within the red brocket deer complex, prompting questions regarding the role of these changes in the speciation process. We propose the red brocket as a model group to investigate how chromosomal changes contribute to isolation and explore the implications of these changes in taxonomy and conservation.
摘要:
染色体重排通常与在物种形成过程中发挥作用有关。然而,有利于与染色体改变相关的遗传隔离的潜在机制仍然难以捉摸。在这个意义上,Mazama属在形态相似的物种中具有高水平的核型多样性。在该属中已鉴定出一种隐秘的物种复合体,红锦鹿(马扎玛美洲和马扎玛rufa)是最令人印象深刻的例子。染色体变异聚集在细胞类型中,二倍体数量为42至53,并与地理位置相关。我们使用不同细胞类型之间的比较染色体绘画和细菌人工染色体(BAC)克隆对红花鹿复合体的染色体进化进行了分析。目的是加深我们对红色布洛克中的核型关系的理解,从而阐明密切相关的物种之间的显着染色体变异。这强调了染色体变化作为塑造其基因组的关键进化过程的重要性。结果表明,存在三种不同的细胞遗传学谱系,其特征是显着的核型分歧,表明存在有效的合子后屏障。串联融合构成了驱动核型进化的主要机制,在几个中心融合之后,倒置X-常染色体融合。BAC作图提高了我们对红花鹿复合体中核型关系的理解,提示有关这些变化在物种形成过程中的作用的问题。我们建议将Redbrocket作为模型组,以研究染色体变化如何促进隔离,并探索这些变化在分类学和保守性方面的意义。