Abstract
Genome functioning in hybrids faces inconsistency. This mismatch is manifested clearly in meiosis during chromosome synapsis and recombination. Species with chromosomal variability can be a model for exploring genomic battles with high visibility due to the use of advanced immunocytochemical methods. We studied synaptonemal complexes (SC) and prophase I processes in 44-chromosome intraspecific (Ellobius tancrei × E. tancrei) and interspecific (Ellobius talpinus × E. tancrei) hybrid mole voles heterozygous for 10 Robertsonian translocations. The same pachytene failures were found for both types of hybrids. In the intraspecific hybrid, the chains were visible in the pachytene stage, then 10 closed SC trivalents formed in the late pachytene and diplotene stage. In the interspecific hybrid, as a rule, SC trivalents composed the SC chains and rarely could form closed configurations. Metacentrics involved with SC trivalents had stretched centromeres in interspecific hybrids. Linkage between neighboring SC trivalents was maintained by stretched centromeric regions of acrocentrics. This centromeric plasticity in structure and dynamics of SC trivalents was found for the first time. We assume that stretched centromeres were a marker of altered nuclear architecture in heterozygotes due to differences in the ancestral chromosomal territories of the parental species. Restructuring of the intranuclear organization and meiotic disturbances can contribute to the sterility of interspecific hybrids, and lead to the reproductive isolation of studied species.
Highlights
IntroductionGenome integrity is crucial for a species; its specificity is supported by reproductive isolation
Genome integrity is crucial for a species; its specificity is supported by reproductive isolation.Hybrid sterility may develop between species or genetically differentiated populations, as a primary or secondary feature of reproductive isolation [1,2,3,4,5]
We studied parental mole vole species—E. talpinus (2n = 54, NF = 54), E. tancrei (2n = 54, NF = 56), and another form of E. tancrei (2n = 34, NF = 56)—and F1 hybrids—intraspecific E. tancrei × E. tancrei
Summary
Genome integrity is crucial for a species; its specificity is supported by reproductive isolation. Hybrid sterility may develop between species or genetically differentiated populations, as a primary or secondary feature of reproductive isolation [1,2,3,4,5]. Two genetic materials in a heterozygous admixed genome interact in various compositions [6] and these hybrid states are often referred to as “genomic conflict” [7,8], “genomic shock” [9,10], “genomic stress” [9,11], or “nucleus at war” [12]. Chromosome differences in hybrid meiocytes can manifest as various irregularities in chromosome synapsis, recombination, chromatin landscape, and transcriptional inactivation [21,22,23,24]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
