RepeatOBserver: tandem repeat visualization and centromere detection
Cassandra Elphinstone,
Rob Elphinstone,
Marco Todesco
et al.
Abstract:Tandem repeats can play an important role in centromere structure, subtelomeric regions, DNA methylation, recombination, and the regulation of gene activity. There is a growing need for bioinformatics tools that can visualize and explore chromosome-scale repeats. Here we present RepeatOBserver, a new tool for visualizing tandem repeats and clustered transposable elements and for identifying potential natural centromere locations, using a Fourier transform of DNA walks: https://github.com/celphin/RepeatOBserver… Show more
“…‘Alphonso’ genome using tandem repeats (±1Mb; SI Appendix, Fig. S2 and Table S1) (33). We discovered half of the regions of major differentiation overlap the predicted centromere (SI Appendix, Table S1), indicating that low recombination regions of the genome might play a role in allowing genetic differentiation in M. indica to persist.…”
Section: Resultsmentioning
confidence: 99%
“…To predict centromere locations on each chromosome, we used RepeatOBserver (33). Centromeres were identified as the regions on each chromosome where the most repeat lengths reached a minimum abundance, implying the dominance of a single centromeric repeating sequence in this window.…”
Chromosomal inversions can preserve combinations of favorable alleles by suppressing recombination. Simultaneously, they reduce the effectiveness of purifying selection enabling deleterious alleles to accumulate. This study explores how areas of low recombination, including centromeric regions and chromosomal inversions, contribute to the accumulation of deleterious and favorable loci in 225 Mangifera indica genomes from the Australian Mango Breeding Program. Here, we identify 17 chromosomal inversions that cover 7.7% (29.7Mb) of the M. indica genome: eight pericentric (inversion includes the centromere) and nine paracentric (inversion is on one arm of the chromosome). Our results show that these large pericentric inversions are accumulating deleterious loci, while the paracentric inversions show deleterious levels above and below the genome wide average. We find that despite their deleterious load, chromosomal inversions contain small effect loci linked to variation in crucial breeding traits, indicating that chromosomal inversions have likely facilitated their selection. The results from this study have important implications for selective breeding of favorable combinations of alleles in regions of low recombination.
“…‘Alphonso’ genome using tandem repeats (±1Mb; SI Appendix, Fig. S2 and Table S1) (33). We discovered half of the regions of major differentiation overlap the predicted centromere (SI Appendix, Table S1), indicating that low recombination regions of the genome might play a role in allowing genetic differentiation in M. indica to persist.…”
Section: Resultsmentioning
confidence: 99%
“…To predict centromere locations on each chromosome, we used RepeatOBserver (33). Centromeres were identified as the regions on each chromosome where the most repeat lengths reached a minimum abundance, implying the dominance of a single centromeric repeating sequence in this window.…”
Chromosomal inversions can preserve combinations of favorable alleles by suppressing recombination. Simultaneously, they reduce the effectiveness of purifying selection enabling deleterious alleles to accumulate. This study explores how areas of low recombination, including centromeric regions and chromosomal inversions, contribute to the accumulation of deleterious and favorable loci in 225 Mangifera indica genomes from the Australian Mango Breeding Program. Here, we identify 17 chromosomal inversions that cover 7.7% (29.7Mb) of the M. indica genome: eight pericentric (inversion includes the centromere) and nine paracentric (inversion is on one arm of the chromosome). Our results show that these large pericentric inversions are accumulating deleterious loci, while the paracentric inversions show deleterious levels above and below the genome wide average. We find that despite their deleterious load, chromosomal inversions contain small effect loci linked to variation in crucial breeding traits, indicating that chromosomal inversions have likely facilitated their selection. The results from this study have important implications for selective breeding of favorable combinations of alleles in regions of low recombination.
Satellite DNAs (satDNAs) are tandemly repeated sequences that make up a significant portion of almost all eukaryotic genomes. Although satDNAs have been shown to play a very important role in genome organization and evolution, they are relatively poorly analysed even in model. One of the main reasons for the current lack of in-depth studies on satDNAs is their underrepresentation in genome assemblies. The complexity and highly repetitive nature of satDNAs make their analysis challenging, and there is a need for efficient tools that can ensure accurate annotation and analysis of satDNAs.We present a novel pipeline, named Satellite DNA Exploration (SatXplor), designed to robustly characterize satDNA elements and analyse their arrays and flanking regions. SatXplor is benchmarked against curated satDNA datasets from diverse species, showcasing its versatility across genomes with varying complexities and different satDNA profile. Component algorithms excel in the identification of tandemly repeated sequences and for the first time enable evaluation of satDNA variation and array annotation with the addition of information about surrounding genomic landscape.SatXplor is an innovative pipeline for satDNA analysis that can be paired with any tool used for satDNA detection, offering insights into the structural characteristics, array determination and genomic context of satDNA elements. By integrating various computational techniques, from sequence analysis and homology investigation to advanced clustering and graph-based methods, it provides a versatile and comprehensive approach to explore the complexity of satDNA organization and to understand the underlying mechanisms and evolutionary aspects. It is open-source and freely accessible athttps://github.com/mvolar/SatXplor.
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