Heteromorphism of “Homomorphic” Sex Chromosomes in Two Anole Species (Squamata, Dactyloidae) Revealed by Synaptonemal Complex Analysis

Lisachov, Artem; Trifonov, Vladimir A.; Giovannotti, Massimo; Ferguson‐Smith, Malcolm A.; Бородин, П. М.

doi:10.1159/000460829

Cited by 10 publications

(5 citation statements)

References 34 publications

(33 reference statements)

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“…Red: SYCP3 , green: centromere and MLH1 , blue: DAPI b, d DAPI channel separately. Arrowheads show the XY bivalent ( Lisachov et al in press ). Arrow shows the DAPI+ band on the SC 2 of Deiroptyx coelestinus .…”

Section: Resultsmentioning

confidence: 99%

Immunocytological analysis of meiotic recombination in two anole lizards (Squamata, Dactyloidae)

Lisachov

Trifonov

Giovannotti³

et al. 2017

CCG

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Although the evolutionary importance of meiotic recombination is not disputed, the significance of interspecies differences in the recombination rates and recombination landscapes remains under-appreciated. Recombination rates and distribution of chiasmata have been examined cytologically in many mammalian species, whereas data on other vertebrates are scarce. Immunolocalization of the protein of the synaptonemal complex (SYCP3), centromere proteins and the mismatch-repair protein MLH1 was used, which is associated with the most common type of recombination nodules, to analyze the pattern of meiotic recombination in the male of two species of iguanian lizards, Anolis carolinensis Voigt, 1832 and Deiroptyx coelestinus (Cope, 1862). These species are separated by a relatively long evolutionary history although they retain the ancestral iguanian karyotype. In both species similar and extremely uneven distributions of MLH1 foci along the macrochromosome bivalents were detected: approximately 90% of crossovers were located at the distal 20% of the chromosome arm length. Almost total suppression of recombination in the intermediate and proximal regions of the chromosome arms contradicts the hypothesis that “homogenous recombination” is responsible for the low variation in GC content across the anole genome. It also leads to strong linkage disequilibrium between the genes located in these regions, which may benefit conservation of co-adaptive gene arrays responsible for the ecological adaptations of the anoles.

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Section: Resultsmentioning

confidence: 99%

Immunocytological analysis of meiotic recombination in two anole lizards (Squamata, Dactyloidae)

Lisachov

Trifonov

Giovannotti³

et al. 2017

CCG

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“…Despite the near complete degeneration of the Y chromosome in iguanids, except for 7 genes [Marin et al, 2017], cytogenetic analysis demonstrates the presence of a relatively large recombining PAR in A . carolinensis [Lisachov et al, 2017], probably lacking genes. Translocation of the same blocks onto both X and Y chromosomes may take over the role of the recombining stratum, thus making the old region redundant and accelerating its degeneration.…”

Section: Discussionmentioning

confidence: 99%

“…Many pleurodont species conserve the ancestral karyotype of all Iguania, consisting of 6 pairs of macrochromosomes and 12 pairs of microchromosomes, and therefore the ancestral condition of the sex chromosomes (although intrachromosomal rearrangements are possible) [Lisachov et al, 2017]. However, in several clades the ancestral sex chromosomes fused with autosomes, forming neosex chromosomes .…”

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confidence: 99%

Genetic Content of the Neo-Sex Chromosomes in Ctenonotus and Norops (Squamata, Dactyloidae) and Degeneration of the Y Chromosome as Revealed by High-Throughput Sequencing of Individual Chromosomes

Lisachov

Makunin

Giovannotti

et al. 2019

Cytogenet Genome Res

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Pleurodont lizards are characterized by an ancient system of sex chromosomes. Along with stability of the central component of the system (homologous to the X chromosome of Anolis carolinensis [Dactyloidae], ACAX), in some genera the ancestral sex chromosomes are fused with microautosomes, forming neo-sex chromosomes. The genus Ctenonotus (Dactyloidae) is characterized by multiple X₁X₁X₂X₂/X₁X₂Y sex chromosomes. According to cytogenetic data, the large neo-Y chromosome is formed by fusion of the ancestral Y chromosome with 2 microautosomes (homologous to ACA10 or ACA11 and ACA12), the X₁ chromosome is formed by fusion of the ancestral X chromosome with the autosome homologous to ACA10 or ACA11, and the X₂ chromosome is homologous to autosome ACA12. To determine more precisely the content and evolution of the Ctenonotus sex chromosomes, we sequenced flow-sorted chromosomes (both sex chromosomes and microautosomes as control) of 2 species with a similar system: C. pogus and C. sabanus. Our results indicate that the translocated part of the X₁ is homologous to ACA11, X₂ is homologous to ACA12, and the Y contains segments homologous to both ACA11 and ACA12. Molecular divergence estimates suggest that the ancestral X-derived part has completely degenerated in the Y of Ctenonotus, similar to the degeneration of the Norops sagrei Y chromosome (Dactyloidae). The newly added regions show loss of DNA content, but without degeneration of the conserved regions. We hypothesize that the translocation of autosomal blocks onto sex chromosomes facilitated rapid degeneration of the pseudoautosomal region on the ancestral Y.

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“…The SC analysis is particularly efficient in detection of heterozygosity for all types of chromosome rearrangements: inversions, translocations, deletions and duplications. The heterozygotes for the structural variants and heterogametic organisms produce characteristic heteromorphic SCs (Poorman et al 1981;del Priore et al 2015;Lisachov et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Pachytene karyotypes of 17 species of birds

Slobodchikova

Malinovskaya

Grishko

et al. 2022

Preprint

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Background: To date less than 10% of bird species have been karyotyped. They are rather conservative with diploid chromosome numbers about 78-80 in most species examined. Immunostaining of meiotic chromosomes at pachytene stage enables more precise estimates of the number, morphology and variability of macro- and microchromosomes than conventional analysis of mitotic metaphase chromosomes does. Analysis of pachytene chromosomes led to discovery of germline-restricted chromosome (GRC) that was present in germline cells and absent in somatic cells in all 16 species of passerine birds examined. GRC has not been found in any non-passerine bird. Results: In this study, using immunolocalization of SYCP3, the main protein of the lateral elements of the synaptonemal complex (SC) and centromere proteins we examined male pachytene karyotypes of sixteen passerine species and one outgroup species the Common cuckoo Cuculus canorus and provided their idiograms and precise estimates of their diploid chromosome numbers and the numbers of chromosome arms. We provided the first description of the karyotypes of three species, corrected the published data on the karyotypes of ten species and confirmed them for four species. The pachytene cells of the Gouldian finch, Brambling and Common linnet contained heteromorphic bivalents indicating heterozygosity for inversions or centromere shifts. The European pied flycatcher, Gouldian finch and Domestic canary have extended centromeres in several macro- and microchromosomes. GRCs of various sizes and shapes were detected in all passerine species examined. Their chromatin was heavily labeled by anticentromere antibodies. The lateral elements of the GRC SC varied in their size from the largest to the smallest element of the pachytene karyotype. They also varied in shape from continuous to fragmented. Conclusions: All songbirds examined, except the Eurasian skylark, have highly conservative karyotypes, 2n=80-82+GRC with seven pairs of macrochromosomes and 33-34 pairs of microchromosomes. The interspecies differences concern the sizes of the macrochromosomes, morphology of the microchromosomes and sizes of the centromeres. GRC is present in all songbird species examined, varying in size, morphology and SC structure even between closely related species. This indicates its fast evolution.

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Heteromorphism of “Homomorphic” Sex Chromosomes in Two Anole Species (Squamata, Dactyloidae) Revealed by Synaptonemal Complex Analysis

Cited by 10 publications

References 34 publications

Immunocytological analysis of meiotic recombination in two anole lizards (Squamata, Dactyloidae)

Immunocytological analysis of meiotic recombination in two anole lizards (Squamata, Dactyloidae)

Genetic Content of the Neo-Sex Chromosomes in <b><i>Ctenonotus</i></b> and <b><i>Norops</i></b> (Squamata, Dactyloidae) and Degeneration of the Y Chromosome as Revealed by High-Throughput Sequencing of Individual Chromosomes

Pachytene karyotypes of 17 species of birds

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