Repetitive Sequence and Sex Chromosome Evolution in Vertebrates

Abstract

Sex chromosomes are the most dynamic entity in any genome having unique morphology, gene content, and evolution. They have evolved multiple times and independently throughout vertebrate evolution. One of the major genomic changes that pertain to sex chromosomes involves the amplification of common repeats. It is hypothesized that such amplification of repeats facilitates the suppression of recombination, leading to the evolution of heteromorphic sex chromosomes through genetic degradation of Y or W chromosomes. Although contrasting evidence is available, it is clear that amplification of simple repetitive sequences played a major role in the evolution of Y and W chromosomes in vertebrates. In this review, we present a brief overview of the repetitive DNA classes that accumulated during sex chromosome evolution, mainly focusing on vertebrates, and discuss their possible role and potential function in this process.

Amplification of microsatellite repeat motifs is associated with the evolutionary differentiation and heterochromatinization of sex chromosomes in Sauropsida

“…Accumulation of repetitive sequences, such as retrotransposons and microsatellite repeats, on sex chromosomes has been reported in many species of animals and plants (for example, Kraemer and Schmidt 1993;Hobza et al 2006;Cioffi and Betrollo 2012;Ezaz et al 2013;Ezaz and Deakin 2014).…”

“…XY and ZW sex chromosome systems show an almost random distribution across the phylogeny of turtles and squamates (Ezaz et al 2009;Organ and Janes 2008;Pokorna and Kratochvil 2009;Sarre et al 2011), suggesting that transitions between sex chromosome systems have occurred many times (Sarre et al 2011), so that sex chromosomes have arisen independently multiple times. Unlike the XY sex chromosomes of mammals, little is known about the origin and differentiation of sex chromosomes in Sauropsida, particularly the role of repetitive sequences (Ezaz and Deakin 2014).…”

Chromosomal Mapping of Repetitive DNAs in <b><i>Myiopsitta monachus</i></b> and <b><i>Amazona aestiva</i></b> (Psittaciformes, Psittacidae) with Emphasis on the Sex Chromosomes

“…In addition, although W chromosomes are usually smaller than Zs in most ZW species, in some groups of vertebrates, the opposite scenario was observed, as in some lizards and fishes, due to a series of amplifications of repetitive elements [Galetti et al, 1995;Ezaz et al, 2009;Schartl et al, 2016]. Indeed, the accumulation of repetitive sequences, like retrotransposons and microsatellites in sex chromosomes, has been reported in many species of plants and animals [Kraemer and Schmidt, 1993;Hobza et al, 2006;Cioffi and Bertollo, 2012;Ezaz et al, 2013;Ezaz and Deakin, 2014].…”

Sex chromosome repeats tip the balance towards speciation

“…For example, despite shared satellites at centromere loci across autosomes, the distribution of satellites varies across the X and Y chromosomes of wallabies (Bulazel, Ferreri, Eldridge, & O'Neill, ) (Figure ). Examples of novel transposable element and/or satellite distribution across sex chromosomes have been reported in many systems, including plants (Charlesworth, ; Cunado et al., ; Hobza et al., , ; Mariotti, Manzano, Kejnovsky, Vyskot, & Jamilena, ; Mariotti et al., ; Navajas‐Pérez et al., ; Shibata, Hizume, & Kuroki, , ; Steflova et al., ; Vyskot & Hobza, ), insects (Blackmon, Ross, & Bachtrog, ; DiBartolomeis, Tartof, & Jackson, ; Khost et al., ; Kuhn & Heslop‐Harrison, ; Palacios‐Gimenez et al., ; Steinemann & Steinemann, ) and vertebrates (Bulazel et al., ; Cioffi, Camacho, & Bertollo, ; Cioffi, Kejnovsky, & Bertollo, ; Cioffi, Molina, Moreira‐Filho, & Bertollo, ; Delany, Gessaro, Rodrigue, & Daniels, ; Ezaz & Deakin, ; Forster et al., ; Kawai et al., ; Kortschak, Tsend‐Ayush, & Grutzner, ; Macdonald et al., ; Miyaki, Hanotte, Wajntal, & Burke, ; Murtagh et al., ; de Oliveira et al., ; Pokorna, Kratochvil, & Kejnovsky, ; Suda, Uno, Mori, Matsuda, & Nakamura, ; Tomaszkiewicz, Medvedev, & Makova, ; Tone, Sakaki, Hashiguchi, & Mizuno, ; Wilson & Makova, ,b; Young, O'Meally, Sarre, Georges, & Ezaz, ), including human (Lander et al., ; Miga et al., ; Ross et al., ; Skaletsky et al., ).…”