TY - JOUR

T1 - 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

AU - Lisachov, Artem P.

AU - Makunin, Alexey I.

AU - Giovannotti, Massimo

AU - Pereira, Jorge C.

AU - Druzhkova, Anna S.

AU - Caputo Barucchi, Vincenzo

AU - Ferguson-Smith, Malcolm A.

AU - Trifonov, Vladimir A.

N1 - Publisher Copyright: © 2019 S. Karger AG, Basel.

PY - 2019/4/1

Y1 - 2019/4/1

N2 - 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 X 1 X 1 X 2 X 2 /X 1 X 2 Y 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 X 1 chromosome is formed by fusion of the ancestral X chromosome with the autosome homologous to ACA10 or ACA11, and the X 2 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 X 1 is homologous to ACA11, X 2 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.

AB - 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 X 1 X 1 X 2 X 2 /X 1 X 2 Y 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 X 1 chromosome is formed by fusion of the ancestral X chromosome with the autosome homologous to ACA10 or ACA11, and the X 2 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 X 1 is homologous to ACA11, X 2 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.

KW - Degeneration

KW - Gonosome evolution

KW - Lizards

KW - Next-generation sequencing

KW - Reptile

KW - Sex chromosomes

KW - KARYOTYPES

KW - ORIGIN

KW - EVOLUTION

KW - TIME

KW - GENOME

KW - Chromosome Painting/methods

KW - Translocation, Genetic

KW - Species Specificity

KW - Male

KW - High-Throughput Nucleotide Sequencing/methods

KW - Lizards/classification

KW - X Chromosome/genetics

KW - Animals

KW - DNA/chemistry

KW - Female

KW - Chromosomes/genetics

KW - Y Chromosome/genetics

UR - http://www.scopus.com/inward/record.url?scp=85062389062&partnerID=8YFLogxK

U2 - 10.1159/000497091

DO - 10.1159/000497091

M3 - Article

C2 - 30820011

AN - SCOPUS:85062389062

VL - 157

SP - 115

EP - 122

JO - Cytogenetic and Genome Research

JF - Cytogenetic and Genome Research

SN - 1424-8581

IS - 1-2

ER -