TY - JOUR

T1 - Identification of Iguania Ancestral Syntenic Blocks and Putative Sex Chromosomes in the Veiled Chameleon (Chamaeleo calyptratus, Chamaeleonidae, Iguania)

AU - Tishakova, Katerina V

AU - Prokopov, Dmitry Yu

AU - Davletshina, Guzel I

AU - Rumyantsev, Alexander V

AU - O'Brien, Patricia C M

AU - Ferguson-Smith, Malcolm A

AU - Giovannotti, Massimo

AU - Lisachov, Artem P

AU - Trifonov, Vladimir A

N1 - Funding: This work was supported by research grant no. 19-54-26017 from the Russian Foundation for Basic Research, the research grant no. 2019-0546 (FSUS-2020-0040) from the Ministry of Science and Higher Education (Russia) via the Novosibirsk State University and the Institute of Cytology and Genetics.

PY - 2022/12/13

Y1 - 2022/12/13

N2 - The veiled chameleon (Chamaeleo calyptratus) is a typical member of the family Chamaeleonidae and a promising object for comparative cytogenetics and genomics. The karyotype of C. calyptratus differs from the putative ancestral chameleon karyotype (2n = 36) due to a smaller chromosome number (2n = 24) resulting from multiple chromosome fusions. The homomorphic sex chromosomes of an XX/XY system were described recently using male-specific RADseq markers. However, the chromosomal pair carrying these markers was not identified. Here we obtained chromosome-specific DNA libraries of C. calyptratus by chromosome flow sorting that were assigned by FISH and sequenced. Sequence comparison with three squamate reptiles reference genomes revealed the ancestral syntenic regions in the C. calyptratus chromosomes. We demonstrated that reducing the chromosome number in the C. calyptratus karyotype occurred through two fusions between microchromosomes and four fusions between micro-and macrochromosomes. PCR-assisted mapping of a previously described Y-specific marker indicates that chromosome 5 may be the sex chromosome pair. One of the chromosome 5 conserved synteny blocks shares homology with the ancestral pleurodont X chromosome, assuming parallelism in the evolution of sex chromosomes from two basal Iguania clades (pleurodonts and acrodonts). The comparative chromosome map produced here can serve as the foundation for future genome assembly of chameleons and vertebrate-wide comparative genomic studies.

AB - The veiled chameleon (Chamaeleo calyptratus) is a typical member of the family Chamaeleonidae and a promising object for comparative cytogenetics and genomics. The karyotype of C. calyptratus differs from the putative ancestral chameleon karyotype (2n = 36) due to a smaller chromosome number (2n = 24) resulting from multiple chromosome fusions. The homomorphic sex chromosomes of an XX/XY system were described recently using male-specific RADseq markers. However, the chromosomal pair carrying these markers was not identified. Here we obtained chromosome-specific DNA libraries of C. calyptratus by chromosome flow sorting that were assigned by FISH and sequenced. Sequence comparison with three squamate reptiles reference genomes revealed the ancestral syntenic regions in the C. calyptratus chromosomes. We demonstrated that reducing the chromosome number in the C. calyptratus karyotype occurred through two fusions between microchromosomes and four fusions between micro-and macrochromosomes. PCR-assisted mapping of a previously described Y-specific marker indicates that chromosome 5 may be the sex chromosome pair. One of the chromosome 5 conserved synteny blocks shares homology with the ancestral pleurodont X chromosome, assuming parallelism in the evolution of sex chromosomes from two basal Iguania clades (pleurodonts and acrodonts). The comparative chromosome map produced here can serve as the foundation for future genome assembly of chameleons and vertebrate-wide comparative genomic studies.

KW - Animals

KW - Male

KW - Synteny/genetics

KW - Lizards/genetics

KW - Sex Chromosomes/genetics

KW - Chromosomes

KW - Genome

KW - Karyotype

KW - Evolution, Molecular

KW - chromosome fusion

KW - repetitive elements

KW - microchromosomes

KW - karyotype evolution

KW - Squamata

KW - reptilia

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85144492589&origin=inward&txGid=d1e82b60e241d0f7cbdb94235f5aa813

UR - https://www.mendeley.com/catalogue/be6b8430-2cb9-3c07-8ca1-388b2edaab59/

U2 - 10.3390/ijms232415838

DO - 10.3390/ijms232415838

M3 - Article

C2 - 36555478

VL - 23

JO - International Journal of Molecular Sciences

JF - International Journal of Molecular Sciences

SN - 1661-6596

IS - 24

M1 - 15838

ER -