Temperature-Induced Sex Reversal in Reptiles: Prevalence, Discovery, and Evolutionary Implications

Sexual Development, Journal Year: 2021, Volume and Issue: 15(1-3), P. 148 - 156

Published: Jan. 1, 2021

Sex reversal is the process by which an individual develops a phenotypic sex that discordant with its chromosomal or genotypic sex. It occurs in many lineages of ectothermic vertebrates, such as fish, amphibians, and at least one agamid scincid reptile species. usually triggered environmental cue alters genetically determined sexual differentiation, but it can also be caused exposure to exogenous chemicals, hormones, pollutants. Despite occurrence both temperature-dependent determination (TSD) genetic (GSD) broadly among reptiles, only 2 species squamates have thus far been demonstrated possess nature (GSD overriding thermal influence). The lack unambiguously identified not necessarily reflection low incidence this trait reptiles. Indeed, may relatively common little known prevalence, mechanisms occurs, consequences for wild under changing climate. In review, we present roadmap discovery outlining various techniques allow new occurrences identified, molecular involved how identify them, approaches assessing impacts populations. We discuss evolutionary implications use central bearded dragon (Pogona vitticeps) eastern three-lined skink (Bassiana duperreyi) examples opposing patterns impacted differently our rapidly Ultimately, review serves highlight importance understanding laboratory populations proposes practical solutions foster future research.

Language: Английский

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Lizards as Model Organisms of Sex Chromosome Evolution: What We Really Know from a Systematic Distribution of Available Data?

Genes, Journal Year: 2021, Volume and Issue: 12(9), P. 1341 - 1341

Published: Aug. 28, 2021

Lizards represent unique model organisms in the study of sex determination and chromosome evolution. Among tetrapods, they are characterized by an unparalleled diversity systems, including temperature-dependent (TSD) genetic (GSD) under either male or female heterogamety. Sex systems also extremely variable lizards. They include simple (XY ZW) multiple (X1X2Y Z1Z2W) encompass all different hypothesized stages diversification heterogametic chromosomes, from homomorphic to heteromorphic completely heterochromatic chromosomes. The co-occurrence TSD, GSD characterizes lizard taxa, which ideal models emergence evolutionary drivers reversal turnover. In this review, we present a synthesis general genome karyotype features non-snakes squamates discuss main theories evidences on evolution their systems. We here provide systematic assessment available data overview cytogenetic molecular methods used for identification, using qualitative quantitative approach.

Language: Английский

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Sex-specific splicing of Z- and W-bornenr5a1alleles suggests sex determination is controlled by chromosome conformation

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(4)

Published: Jan. 24, 2022

Significance Reptiles have an extraordinary variety of mechanisms to determine sex. The best candidate sex-determining gene in our model reptile (the Australian central bearded dragon) is the key vertebrate sex nr5a1 (coding for steroidogenic factor 1). There are no sex-specific sequence differences between alleles on chromosomes, but Z- and W-borne transcribed into remarkably different alternative transcripts. We propose that altered configuration repeat-laden W chromosome affects conformation primary transcript generate more diverse potentially inhibitory isoforms suppress testis determination. This a mechanism determination, which epigenetic control regulates action present both chromosomes.

Language: Английский

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High elevation increases the risk of Y chromosome loss in Alpine skink populations with sex reversal

Heredity, Journal Year: 2021, Volume and Issue: 126(5), P. 805 - 816

Published: Feb. 1, 2021

The view that has genotypic sex determination and environmental as mutually exclusive states in fishes reptiles been contradicted by the discovery chromosomal influences can co-exist within same species, hinting at a continuum of intermediate states. Systems where genes environment interact to determine present opportunity for reversal occur, phenotypic is opposite predicted their chromosome complement. skink Bassiana duperreyi XX/XY chromosomes with XX genotype male phenotype, laboratory experiments, field nests, response exposure cold incubation temperatures. Here we studied frequency adult populations B. climatic variation, using elevation surrogate We demonstrate wild first time adults reptile species determination. highest occurred coolest location, Mt Ginini (18.46%) decreased zero decreasing elevation. model impact this under Fisher's frequency-dependent selection show that, elevations, risk loss Y transition temperature-dependent This study contributes our understanding risks extinction from climate change subject temperature, will provide focus future research test on-the-ground management strategies mitigate effects local populations.

Language: Английский

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Males can adjust offspring sex ratio in an adaptive fashion through different mechanisms

BioEssays, Journal Year: 2021, Volume and Issue: 43(5)

Published: Feb. 16, 2021

Abstract Sex allocation research has primarily focused on offspring sex‐ratio adjustment by mothers. Yet, fathers also benefit from producing more of the sex with greater fitness returns. Here, we review state‐of‐the art in study male‐driven and, counter to current paradigm, propose that males can adaptively influence ratio through a wide variety mechanisms. This includes differential production and motility X‐ versus Y‐bearing sperms mammals, variation seminal fluid composition haplo‐diploid invertebrates, epigenetic mechanisms some fish lizards exhibiting environmental determination. Conflicts interest between mothers over ratios emerge, although many studies are needed this area. While have adaptive explanations little attention mechanisms, vice versa, integration these two topics is essential for understanding allocation.

Language: Английский

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Genomes of two Extinct‐in‐the‐Wild reptiles from Christmas Island reveal distinct evolutionary histories and conservation insights

Molecular Ecology Resources, Journal Year: 2023, Volume and Issue: unknown

Published: March 6, 2023

Genomics can play important roles in biodiversity conservation, especially for Extinct-in-the-Wild species where genetic factors greatly influence risk of total extinction and probability successful reintroductions. The Christmas Island blue-tailed skink (Cryptoblepharus egeriae) Lister's gecko (Lepidodactylus listeri) are two endemic reptile that went extinct the wild shortly after introduction a predatory snake. After decade management, captive populations have expanded from 66 skinks 43 geckos to several thousand individuals; however, little is known about patterns variation these species. Here, we use PacBio HiFi long-read Hi-C sequencing generate highly contiguous reference genomes both reptiles, including XY chromosome pair skink. We then analyse diversity infer ancient demography more recent histories inbreeding. observe high genome-wide heterozygosity (0.007 heterozygous sites per base-pair) (0.005), consistent with large historical population sizes. However, nearly 10% genome falls within long (>1 Mb) runs homozygosity (ROH), resulting at all major histocompatibility complex (MHC) loci. In contrast, detect single ROH gecko. lengths related may established populations. Despite shared wild, our results suggest differences species' implications management. show how contribute evolutionary conservation insights, provide resources future population-level comparative genomic studies reptiles.

Language: Английский

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Sex Chromosomes and Master Sex-Determining Genes in Turtles and Other Reptiles

Genes, Journal Year: 2021, Volume and Issue: 12(11), P. 1822 - 1822

Published: Nov. 19, 2021

Among tetrapods, the well differentiated heteromorphic sex chromosomes of birds and mammals have been highly investigated their master sex-determining (MSD) gene, Dmrt1 SRY, respectively, identified. The homomorphic reptiles least studied, but gap with has begun to fill. This review describes our current knowledge reptilian at cytogenetic molecular level. Most it arose recently from various studies comparing male female gene content. includes restriction site-associated DNA sequencing (RAD-Seq) experiments in several samples, RNA identification Z- or X-linked genes by male/female comparative transcriptome coverage, transcriptomic transcriptome/genome substraction approaches allowing Y- W-linked transcripts. A few putative proposed, none demonstrated yet. Lastly, future directions field MSD are considered.

Language: Английский

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Australian lizards are outstanding models for reproductive biology research

Australian Journal of Zoology, Journal Year: 2021, Volume and Issue: 68(4), P. 168 - 199

Published: Sept. 28, 2021

Australian lizards are a diverse group distributed across the continent and inhabiting wide range of environments. Together, they exhibit remarkable diversity reproductive morphologies, physiologies, behaviours that is broadly representative vertebrates in general. Many traits exhibited by have evolved independently multiple lizard lineages, including sociality, complex signalling mating systems, viviparity, temperature-dependent sex determination. thus outstanding model organisms for testing hypotheses about how function evolve, provide an important basis comparison with other animals similar traits. We review research on reproduction has contributed to answering broader evolutionary ecological questions apply focus traits, processes, strategies areas current research, involved courtship; mechanisms mating, egg production, sperm competition; nesting gestation; determination; finally, birth viviparous species. use our identify emerge from understanding this body when considered holistically. Finally, we additional within each topic well suited biologists address.

Language: Английский

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Using a Handful of Transcriptomes to Detect Sex-Linked Markers and Develop Molecular Sexing Assays in a Species with Homomorphic Sex Chromosomes

Genome Biology and Evolution, Journal Year: 2024, Volume and Issue: 16(4)

Published: March 25, 2024

Abstract To understand the biology of a species, it is often crucial to be able differentiate males and females. However, many species lack easily identifiable sexually dimorphic traits. In those that possess sex chromosomes, molecular sexing offers good alternative, assays can developed through comparison male female genomic sequences. in nonmodel chromosomes are poorly differentiated, identifying sex-linked sequences developing challenging. this study, we highlight simple transcriptome-based procedure for detection markers suitable development circumvents limitations more commonly used approaches. We apply spotted snow skink Carinascincus ocellatus, viviparous lizard with homomorphic XY has environmentally induced reversal. With transcriptomes from three females alone, identify thousands putative Y-linked confirm linkage alignment assembled transcripts distantly related genome readily design multiple single locus polymerase chain reaction primers C. ocellatus species. Our approach also facilitates valuable comparisons determining systems on broad taxonomic scale.

Language: Английский

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Lineage diversity within a widespread endemic Australian skink to better inform conservation in response to regional‐scale disturbance

Ecology and Evolution, Journal Year: 2022, Volume and Issue: 12(3)

Published: March 1, 2022

Abstract Much attention is paid in conservation planning to the concept of a species, ensure comparability across studies and regions when classifying taxa against criteria endangerment setting priorities for action. However, various jurisdictions now allow taxonomic ranks below level species nontaxonomic intraspecific divisions be factored into planning—subspecies, key populations, evolutionarily significant units, or designatable units. Understanding patterns genetic diversity its distribution landscape component identification boundaries determination substantial geographic structure within species. A total 12,532 reliable polymorphic SNP loci were generated from 63 populations (286 individuals) covering Australian eastern three‐lined skink, Bassiana duperreyi , assess population form diagnosable lineages their landscape, with particular reference recent catastrophic bushfires Australia. Five well‐supported operational units (OTUs) existed B . Low levels divergence between mainland Australia Tasmania (no fixed allelic differences) support notion episodic exchange alleles Bass Strait ( ca 60 m, 25 Kya) during periods low sea Upper Pleistocene rather than much longer period isolation (1.7 My) indicated by earlier using mitochondrial sequence variation. Our study provides foundational work detailed re‐evaluation this complex need biodiversity assessment include an examination cryptic and/or Such information on lineage context disturbance at regional scale can regardless whether decision made formally diagnose new taxonomically nomenclaturally.

Language: Английский

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