Chromosomal Differentiation of Deschampsia (Poaceae) Based on Four Satellite DNA Families

Abstract

Diverse families of satellite DNA (satDNA) were detected in heterochromatin regions of Deschampsia. This kind of repetitive DNA consists of tandem repeat sequences forming big arrays in genomes, and can contribute to lineages differentiation. The differentiation between types of satDNA is related to their sequence identity, the size and number of monomers forming the array, and their chromosomal location. In this work, four families of satDNA (D2, D3, D12, D13), previously isolated by genomic analysis, were studied on chromosomal preparations of 12 species of Deschampsia (D. airiformis, D. antarctica, D. cespitosa, D. cordillerarum, D. elongata, D. kingii, D. laxa, D. mendocina, D. parvula, D. patula, D. venustula, and Deschampsia sp) and one of Deyeuxia (D. eminens). Despite the number of satDNA loci showing interspecific variation, the general distribution pattern of each satDNA family is maintained. The four satDNA families are AT-rich and associated with DAPI + heterochromatin regions. D2, D3, and D12 have mainly subterminal distribution, while D13 is distributed in intercalary regions. Such conservation of satDNA patterns suggests a not random distribution in genomes, where the variation between species is mainly associated with the array size and the loci number. The presence of satDNA in all species studied suggests a low genetic differentiation of sequences. On the other hand, the variation of the distribution pattern of satDNA has no clear association with phylogeny. This may be related to high differential amplification and contraction of sequences between lineages, as explained by the library model.

Repeatome Analyses and Satellite DNA Chromosome Patterns in Deschampsia sukatschewii, D. cespitosa, and D. antarctica (Poaceae)

“…Several Ds satDNAs exhibited only specific clustered localization on chromosomes of all studied species, which allowed us to explore interspecific variations in their distribution on chromosomes. These results were consistent with earlier reported data on patterns of chromosomal distribution of CON/COM and Da satDNAs in several Deschampsia species [25,34,35].…”

“…Having many advantages (e.g., it does not require a reference genome for contigs assembling, offers an easy-to-use interface, a rather fast analysis with detailed results), these pipelines are frequently used to create repeat databases and also to identify satDNAs suitable as FISH probes for further molecular cytogenetics [29][30][31][32][33]. Recently, a number of satDNAs were identified in genomes of South American accessions of D. antarctica and D. cespitosa, and also chromosomal distribution of some satDNAs were analyzed in several Deschampsia species growing in the same region [34,35]. However, for a thorough understanding of the relationship between species within the genus Deschampsia, further studies of the genomic diversity are needed.…”

The spread of satellite DNAs in euchromatin and insights into the multiple sex chromosome evolution in Hemiptera revealed by repeatome analysis of the bug Oxycarenus hyalinipennis

“…They are frequently located in pericentromeric and terminal regions of the chromosomes. However, intercalary heterochromatin also exhibits occurrence of satDNAs (de Lima et al, 2020; García‐Souto et al, 2017; González et al, 2021; Gutiérrez et al, 2022). Additionally, some examples of satDNAs populating euchromatin have been reported, albeit in smaller quantities (Garrido‐Ramos, 2017).…”