DOI: 10.5061/dryad.k6t0s
title: Data from: Evolutionary dynamics of the gametologous CTNNB1 gene on the Z and W chromosomes of snakes

description: Snakes exhibit genotypic sex determination with female heterogamety (ZZ
 males and ZW females), and the state of sex chromosome differentiation
 also varies among lineages. To investigate the evolutionary history of
 homologous genes located in the non-recombining region of differentiated
 sex chromosomes in snakes, partial sequences of the gametologous CTNNB1
 gene were analyzed for 12 species belonging to henophid (Cylindrophiidae,
 Xenopeltidae, and Pythonidae) and caenophid snakes (Viperidae, Elapidae,
 and Colubridae). Nonsynonymous/synonymous substitution ratios (Ka/Ks) in
 coding sequences were low (Ka/Ks &lt; 1) between CTNNB1Z and CTNNB1W,
 suggesting that these two genes may have similar functional properties.
 However, frequencies of intron sequence substitutions and
 insertion-deletions were higher in CTNNB1Z than CTNNB1W, suggesting that
 Z-linked sequences evolved faster than W-linked sequences. Molecular
 phylogeny based on both intron and exon sequences showed the presence of
 two major clades: (1) Z-linked sequences of Caenophidia, and (2) W-linked
 sequences of Caenophidia clustered with Z-linked sequences of Henophidia,
 which suggests that the sequence divergence between CTNNB1Z and CTNNB1W in
 Caenophidia may have occurred by the cessation of recombination after the
 split from Henophidia.
description: Supplementary
 fileSupplementary file
 includes supplementary figures and tables, which are relevant to
 publication. Please note that the supplementary tables included in this
 PDF are also uploaded separately, as .xlsx files.Snakes in this
 studySnake samples
 (figure/species) used in this study.Table
 S1Species and nucleotides
 sequences of the CTNNB1 gene used in this study. Table is also available
 in PDF format in the "Supplementary file" PDFTable_S1.xlsxTable_S2Pair-wise comparison of amino acid sequence identities (%) of CTNNB1W among eight snake species. Table is also available in PDF format in the "Supplementary file" PDFTable_S3Frequencies of synonymous and nonsynonymous substitutions in the exon11 of male-derived CTNNB1Z sequences among eight snake species. Ks values are shown above the diagonal, and Ka values are shown below the diagonal. Standard errors are indicated in all values. Table is also available in PDF format in the "Supplementary file" PDFTable_S4Frequencies of synonymous and nonsynonymous substitutions in the exon 11 of female-derived CTNNB1Z sequences among eight snake species. Ks values are shown above the diagonal, and Ka values are shown below the diagonal. Standard errors are indicated in all values. Table is also available in PDF format in the "Supplementary file" PDFTable_S5Frequencies of nonsynonymous/synonymous substitution ratios (Ka/Ks) in exon 11 of the CTNNB1 gene among eight snake species. The CTNNB1W gene is shown above the diagonal with the CTNNB1Z gene below the diagonal. Table is also available in PDF format in the "Supplementary file" PDFTable_S6Nucleotide sequence divergence (Kz) in intron10 and intron 11 of male-derived CTNNB1Z sequences among eight snake species (below diagonal), and female-derived CTNNB1Z sequences (above diagonal). Standard errors are indicated for all values. Table is also available in PDF format in the "Supplementary file" PDF