Chromosome Evolution and Diversification in North American Spiny Lizards (Genus &lt;i&gt;Sceloporus&lt;/i&gt;)

Leaché, Adam D.; Sites, Jack W.

doi:10.1159/000293285

Cited by 33 publications

(40 citation statements)

References 121 publications

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“…Data on sex determination was collected from the literature [Olmo, 2005;Olmo and Signorino, 2005;Vogt, 2008;Leaché and Sites, 2009;Paez et al, 2009;Pokorná and Kratochvíl, 2009;Shibaike et al, 2009;Bernhard, 2010;Okada et al, 2010;Zhang et al, 2010;Hare et al, 2011;Valenzuela and Adams, 2011;Inamdar et al, 2012;Rojo et al, 2012;Tang et al, 2012;Valenzuela et al, 2013]. Lizards are paraphyletic with snakes nested within this clade.…”

mentioning

confidence: 99%

Molecular Cytogenetic Search for Cryptic Sex Chromosomes in Painted Turtles Chrysemys picta

Valenzuela

Badenhorst

Montiel

et al. 2014

Cytogenet Genome Res

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Sex determination is triggered by factors ranging from genotypic (GSD) to environmental (ESD), or both GSD + EE (GSD susceptible to environmental effects), and its evolution remains enigmatic. The presence/absence of sex chromosomes purportedly separates species at the ESD end of the continuum from the rest (GSD and GSD + EE) because the evolutionary dynamics of sex chromosomes and autosomes differ. However, studies suggest that turtles with temperature-dependent sex determination (TSD) are cryptically GSD and possess sex chromosomes. Here, we test this hypothesis in painted turtles Chrysemys picta (TSD), using comparative-genome-hybridization (CGH), a technique known to detect morphologically indistinguishable sex chromosomes in other turtles and reptiles. Our results show no evidence for the existence of sex chromosomes in painted turtles. While it remains plausible that cryptic sex chromosomes may exist in TSD turtles that are characterized by minor genetic differences that cannot be detected at the resolution of CGH, previous attempts have failed to identify sex-specific markers. Genomic sequencing should prove useful in providing conclusive evidence in this regard. If such efforts uncover sex chromosomes in TSD turtles, it may reveal the existence of a fundamental constraint for the evolution of a full spectrum of sex determination (from pure GSD to pure TSD) that is predicted theoretically. Finding sex chromosomes in ESD organisms would question whether pure ESD mechanisms exist at all in nature, or whether those systems currently considered pure ESD simply await the characterization of an underlying GSD architecture.

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confidence: 99%

Molecular Cytogenetic Search for Cryptic Sex Chromosomes in Painted Turtles Chrysemys picta

Valenzuela

Badenhorst

Montiel

et al. 2014

Cytogenet Genome Res

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“…Among amphibians, Y-autosome fusions occur in some 12 species of terraranan frogs, genera Strabomantis , Pristimantis , and Eleutherodactylus [Schmid et al, 2002[Schmid et al, , 2003[Schmid et al, , 2010. Both Y-autosome and W-autosome fusions are known to occur in cypriniform, cyprinodontiform, perciform, salmoniform, and tetraodontiform fishes [de Oliviera et al, 2008;Rao et al, 2009] and, among reptiles, in gekkonid, iguanid, teiid, and scincid lizards, and elapid snakes 310 [Leaché and Sites, 2009;Oguiura et al, 2009]. Such translocations are also known among various mammals [Schmid et al, 2010].…”

Section: Discussionmentioning

confidence: 99%

Evidence for Sex Chromosome Turnover in Proteid Salamanders

Sessions¹,

Mali²,

Green³

et al. 2016

Cytogenet Genome Res

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A major goal of genomic and reproductive biology is to understand the evolution of sex determination and sex chromosomes. Species of the 2 genera of the Salamander family Proteidae - Necturus of eastern North America, and Proteus of Southern Europe - have similar-looking karyotypes with the same chromosome number (2n = 38), which differentiates them from all other salamanders. However, Necturus possesses strongly heteromorphic X and Y sex chromosomes that Proteus lacks. Since the heteromorphic sex chromosomes of Necturus were detectable only with C-banding, we hypothesized that we could use C-banding to find sex chromosomes in Proteus. We examined mitotic material from colchicine-treated intestinal epithelium, and meiotic material from testes in specimens of Proteus, representing 3 genetically distinct populations in Slovenia. We compared these results with those from Necturus. We performed FISH to visualize telomeric sequences in meiotic bivalents. Our results provide evidence that Proteus represents an example of sex chromosome turnover in which a Necturus-like Y-chromosome has become permanently translocated to another chromosome converting heteromorphic sex chromosomes to homomorphic sex chromosomes. These results may be key to understanding some unusual aspects of demographics and reproductive biology of Proteus, and are discussed in the context of models of the evolution of sex chromosomes in amphibians.

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“…There have been few explicitly phylogenetic analyses of karyotype data (Flores et al 2008;Leache and Sites 2009;Henning et al 2011;Maddison and Leduc-Robert 2013), and to our knowledge, our analysis provides the first estimates of transition rates for sex chromosome turnover, Y chromosome decay, and Y chromosome loss, over such a large number of species. We find distinctly different patterns and rates of sex chromosome transitions between the two main suborders of beetles (Adephaga and Polyphaga).…”

Section: Sex Chromosome Evolution In Coleopteramentioning

confidence: 96%

Estimating Tempo and Mode of Y Chromosome Turnover: Explaining Y Chromosome Loss With the Fragile Y Hypothesis

Blackmon

Demuth

2014

Genetics

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Chromosomal sex determination is phylogenetically widespread, having arisen independently in many lineages. Decades of theoretical work provide predictions about sex chromosome differentiation that are well supported by observations in both XY and ZW systems. However, the phylogenetic scope of previous work gives us a limited understanding of the pace of sex chromosome gain and loss and why Y or W chromosomes are more often lost in some lineages than others, creating XO or ZO systems. To gain phylogenetic breadth we therefore assembled a database of 4724 beetle species' karyotypes and found substantial variation in sex chromosome systems. We used the data to estimate rates of Y chromosome gain and loss across a phylogeny of 1126 taxa estimated from seven genes. Contrary to our initial expectations, we find that highly degenerated Y chromosomes of many members of the suborder Polyphaga are rarely lost, and that cases of Y chromosome loss are strongly associated with chiasmatic segregation during male meiosis. We propose the "fragile Y" hypothesis, that recurrent selection to reduce recombination between the X and Y chromosome leads to the evolution of a small pseudoautosomal region (PAR), which, in taxa that require XY chiasmata for proper segregation during meiosis, increases the probability of aneuploid gamete production, with Y chromosome loss. This hypothesis predicts that taxa that evolve achiasmatic segregation during male meiosis will rarely lose the Y chromosome. We discuss data from mammals, which are consistent with our prediction.

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Chromosome Evolution and Diversification in North American Spiny Lizards (Genus <i>Sceloporus</i>)

Cited by 33 publications

References 121 publications

Molecular Cytogenetic Search for Cryptic Sex Chromosomes in Painted Turtles <b><i>Chrysemys picta</i></b>

Molecular Cytogenetic Search for Cryptic Sex Chromosomes in Painted Turtles <b><i>Chrysemys picta</i></b>

Evidence for Sex Chromosome Turnover in Proteid Salamanders

Estimating Tempo and Mode of Y Chromosome Turnover: Explaining Y Chromosome Loss With the Fragile Y Hypothesis

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