TY - JOUR

T1 - Amplified fragments of an autosome-borne gene constitute a significant component of the w sex chromosome of eremias velox (Reptilia, lacertidae)

AU - Lisachov, Artem

AU - Andreyushkova, Daria

AU - Davletshina, Guzel

AU - Prokopov, Dmitry

AU - Romanenko, Svetlana

AU - Galkina, Svetlana

AU - Saifitdinova, Alsu

AU - Simonov, Evgeniy

AU - Borodin, Pavel

AU - Trifonov, Vladimir

N1 - Funding Information: Funding: The work was supported by the research grant #19-14-00050 from the Russian Science Foundation, the research grant #19-54-26017 from the Russian Foundation for Basic Research, the research grants #2019-0546 (FSUS-2020-0040) and #0324-2019-0042 from the Ministry of Science and Higher Education (Russia) via the Novosibirsk State University and the Institute of Cytology and Genetics. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/5/20

Y1 - 2021/5/20

N2 - Heteromorphic W and Y sex chromosomes often experience gene loss and heterochromatinization, which is frequently viewed as their “degeneration”. However, the evolutionary trajectories of the heterochromosomes are in fact more complex since they may not only lose but also acquire new sequences. Previously, we found that the heterochromatic W chromosome of a lizard Eremias velox (Lacertidae) is decondensed and thus transcriptionally active during the lampbrush stage. To determine possible sources of this transcription, we sequenced DNA from a microdissected W chromosome sample and a total female DNA sample and analyzed the results of reference-based and de novo assembly. We found a new repetitive sequence, consisting of fragments of an autosomal protein-coding gene ATF7IP2, several SINE elements, and sequences of unknown origin. This repetitive element is distributed across the whole length of the W chromosome, except the centromeric region. Since it retained only 3 out of 10 original ATF7IP2 exons, it remains unclear whether it is able to produce a protein product. Subsequent studies are required to test the presence of this element in other species of Lacertidae and possible functionality. Our results provide further evidence for the view of W and Y chromosomes as not just “degraded” copies of Z and X chromosomes but independent genomic segments in which novel genetic elements may arise.

AB - Heteromorphic W and Y sex chromosomes often experience gene loss and heterochromatinization, which is frequently viewed as their “degeneration”. However, the evolutionary trajectories of the heterochromosomes are in fact more complex since they may not only lose but also acquire new sequences. Previously, we found that the heterochromatic W chromosome of a lizard Eremias velox (Lacertidae) is decondensed and thus transcriptionally active during the lampbrush stage. To determine possible sources of this transcription, we sequenced DNA from a microdissected W chromosome sample and a total female DNA sample and analyzed the results of reference-based and de novo assembly. We found a new repetitive sequence, consisting of fragments of an autosomal protein-coding gene ATF7IP2, several SINE elements, and sequences of unknown origin. This repetitive element is distributed across the whole length of the W chromosome, except the centromeric region. Since it retained only 3 out of 10 original ATF7IP2 exons, it remains unclear whether it is able to produce a protein product. Subsequent studies are required to test the presence of this element in other species of Lacertidae and possible functionality. Our results provide further evidence for the view of W and Y chromosomes as not just “degraded” copies of Z and X chromosomes but independent genomic segments in which novel genetic elements may arise.

KW - ATF7IP2

KW - Heterochromatin

KW - Lizards

KW - Repetitive DNA

KW - Sex chromosomes

UR - http://www.scopus.com/inward/record.url?scp=85107448003&partnerID=8YFLogxK

U2 - 10.3390/genes12050779

DO - 10.3390/genes12050779

M3 - Article

C2 - 34065205

AN - SCOPUS:85107448003

VL - 12

SP - NA

JO - Genes

JF - Genes

SN - 2073-4425

IS - 5

M1 - 779

ER -