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Karyotype Reorganization in the Hokou Gecko (Gekko hokouensis, Gekkonidae): The Process of Microchromosome Disappearance in Gekkota.

Srikulnath K, Uno Y, Nishida C, Ota H, Matsuda Y - PLoS ONE (2015)

Bottom Line: Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG).However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis.These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan; Laboratory of Animal Cytogenetics and Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok, Thailand; Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University (CASTNAR, NRU-KU), Kasetsart University, Bangkok, Thailand.

ABSTRACT
The Hokou gecko (Gekko hokouensis: Gekkonidae, Gekkota, Squamata) has the chromosome number 2n = 38, with no microchromosomes. For molecular cytogenetic characterization of the gekkotan karyotype, we constructed a cytogenetic map for G. hokouensis, which retains the ancestral karyotype of Gekkota, with 86 functional genes, and compared it with cytogenetic maps for four Toxicofera species that have many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) and that for a lacertid species (Lacerta agilis) with only one pair of autosomal microchromosomes. Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG). However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis. These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.

No MeSH data available.


Cytogenetic map of Gekko hokouensis, which shows chromosome homologies with the chicken and five squamate reptiles.This map was constructed with 86 functional genes and 18S–28S and 5S rRNA genes. Chromosomal locations of ATP5A1, GHR, CHD1, DMRT1, RPS6, and ACO1/IREBP were obtained from Kawai et al. [39]. The idiogram of G. hokouensis chromosomes was constructed according to Hoechst 33258-stained band patterns. Locations of the genes on G. hokouensis chromosomes are shown to the right of the chromosomes. The chromosome numbers show the chromosomes of the chicken (Gallus gallus, GGA), green anole (Anolis carolinensis, ACA), butterfly lizard (Leiolepis reevesii rubritaeniata, LRE), Japanese four-striped rat snake (Elaphe quadrivirgata, EQU), water monitor lizard (Varanus salvator macromaculatus, VSA), and sand lizard (Lacerta agilis, LAG), which show homologies with G. hokouensis chromosomes. no, no data on chromosome homology; un, a gene whose chromosomal location remains undetermined. Orange highlight indicates the genes that are homologous to chromosome segments of LAG. These genes are located on LRE, EQU, or VSA microchromosomes. The chromosomal locations of genes in the squamate reptiles were obtained from the following sources: L. reevesii rubritaeniata from Srikulnath et al. [11], A. carolinensis from Alföldi et al. [14], E. quadrivirgata from Matsubara et al. [9, 10], V. salvator macromaculatus from Srikulnath et al. [12], and L. agilis from Srikulnath et al. [13].
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pone.0134829.g004: Cytogenetic map of Gekko hokouensis, which shows chromosome homologies with the chicken and five squamate reptiles.This map was constructed with 86 functional genes and 18S–28S and 5S rRNA genes. Chromosomal locations of ATP5A1, GHR, CHD1, DMRT1, RPS6, and ACO1/IREBP were obtained from Kawai et al. [39]. The idiogram of G. hokouensis chromosomes was constructed according to Hoechst 33258-stained band patterns. Locations of the genes on G. hokouensis chromosomes are shown to the right of the chromosomes. The chromosome numbers show the chromosomes of the chicken (Gallus gallus, GGA), green anole (Anolis carolinensis, ACA), butterfly lizard (Leiolepis reevesii rubritaeniata, LRE), Japanese four-striped rat snake (Elaphe quadrivirgata, EQU), water monitor lizard (Varanus salvator macromaculatus, VSA), and sand lizard (Lacerta agilis, LAG), which show homologies with G. hokouensis chromosomes. no, no data on chromosome homology; un, a gene whose chromosomal location remains undetermined. Orange highlight indicates the genes that are homologous to chromosome segments of LAG. These genes are located on LRE, EQU, or VSA microchromosomes. The chromosomal locations of genes in the squamate reptiles were obtained from the following sources: L. reevesii rubritaeniata from Srikulnath et al. [11], A. carolinensis from Alföldi et al. [14], E. quadrivirgata from Matsubara et al. [9, 10], V. salvator macromaculatus from Srikulnath et al. [12], and L. agilis from Srikulnath et al. [13].

Mentions: Eighty genes were newly mapped to G. hokouensis chromosomes in the present study, in addition to six Z-linked genes (ATP5A1, GHR, CHD1, DMRT1, RPS6, and ACO1/IREBP) that were mapped in our previous study [39]. We constructed a cytogenetic map for G. hokouensis with 86 functional genes (Figs 3–5), and to the best of our knowledge, this is the first comprehensive cytogenetic map for gekkotan lizards. More than 40 metaphase spreads were observed for each gene, with hybridization efficiencies ranging from approximately 30% to 80%. Chromosome homology between G. hokouensis and the chicken was analyzed using the chicken genome database (http://www.ncbi.nlm.nih.gov/genome/guide/chicken/). Nine genes that were mapped to G. hokouensis chromosome (GHO) 1 were localized to chicken (Gallus gallus) chromosomes (GGA) 3, 12, 13, 16, and 18 (Table 1, Figs 3 & 4). Five genes mapped to GHO2 were localized to GGA5 and GGA7. Seven genes on GHO3 were located on GGA8, GGA20, GGA26, and GGA28. GHO4 (the Z sex chromosome) corresponded to GGAZ, and GHO5 showed homology with GGA4p and GGA23. Five genes on GHO6 were localized to GGA2q, GGA10, and GGA13, and six genes on GHO7 were localized to GGA4q. GHO8 was homologous to GGA2p (Figs 3 & 4). GHO9 showed homology with GGA17, GGA21, and GGA25; GHO10, with GGA14 and GGA24; GHO11, with GGA15; and GHO12, with GGA27. Six genes on GHO13 were located on GGA1q and GGA11. GHO14 was homologous to GGA1p; and GHO15, to GGA6 and GGA9 (Figs 3 & 4). The chromosomal location of KRT8, which has not been determined in the chicken, was mapped to GHO16, and TRIM37 and AMH located on GHO17 were localized to GGA19. No functional genes were mapped to GHO18 and GHO19 in the present study.


Karyotype Reorganization in the Hokou Gecko (Gekko hokouensis, Gekkonidae): The Process of Microchromosome Disappearance in Gekkota.

Srikulnath K, Uno Y, Nishida C, Ota H, Matsuda Y - PLoS ONE (2015)

Cytogenetic map of Gekko hokouensis, which shows chromosome homologies with the chicken and five squamate reptiles.This map was constructed with 86 functional genes and 18S–28S and 5S rRNA genes. Chromosomal locations of ATP5A1, GHR, CHD1, DMRT1, RPS6, and ACO1/IREBP were obtained from Kawai et al. [39]. The idiogram of G. hokouensis chromosomes was constructed according to Hoechst 33258-stained band patterns. Locations of the genes on G. hokouensis chromosomes are shown to the right of the chromosomes. The chromosome numbers show the chromosomes of the chicken (Gallus gallus, GGA), green anole (Anolis carolinensis, ACA), butterfly lizard (Leiolepis reevesii rubritaeniata, LRE), Japanese four-striped rat snake (Elaphe quadrivirgata, EQU), water monitor lizard (Varanus salvator macromaculatus, VSA), and sand lizard (Lacerta agilis, LAG), which show homologies with G. hokouensis chromosomes. no, no data on chromosome homology; un, a gene whose chromosomal location remains undetermined. Orange highlight indicates the genes that are homologous to chromosome segments of LAG. These genes are located on LRE, EQU, or VSA microchromosomes. The chromosomal locations of genes in the squamate reptiles were obtained from the following sources: L. reevesii rubritaeniata from Srikulnath et al. [11], A. carolinensis from Alföldi et al. [14], E. quadrivirgata from Matsubara et al. [9, 10], V. salvator macromaculatus from Srikulnath et al. [12], and L. agilis from Srikulnath et al. [13].
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4524605&req=5

pone.0134829.g004: Cytogenetic map of Gekko hokouensis, which shows chromosome homologies with the chicken and five squamate reptiles.This map was constructed with 86 functional genes and 18S–28S and 5S rRNA genes. Chromosomal locations of ATP5A1, GHR, CHD1, DMRT1, RPS6, and ACO1/IREBP were obtained from Kawai et al. [39]. The idiogram of G. hokouensis chromosomes was constructed according to Hoechst 33258-stained band patterns. Locations of the genes on G. hokouensis chromosomes are shown to the right of the chromosomes. The chromosome numbers show the chromosomes of the chicken (Gallus gallus, GGA), green anole (Anolis carolinensis, ACA), butterfly lizard (Leiolepis reevesii rubritaeniata, LRE), Japanese four-striped rat snake (Elaphe quadrivirgata, EQU), water monitor lizard (Varanus salvator macromaculatus, VSA), and sand lizard (Lacerta agilis, LAG), which show homologies with G. hokouensis chromosomes. no, no data on chromosome homology; un, a gene whose chromosomal location remains undetermined. Orange highlight indicates the genes that are homologous to chromosome segments of LAG. These genes are located on LRE, EQU, or VSA microchromosomes. The chromosomal locations of genes in the squamate reptiles were obtained from the following sources: L. reevesii rubritaeniata from Srikulnath et al. [11], A. carolinensis from Alföldi et al. [14], E. quadrivirgata from Matsubara et al. [9, 10], V. salvator macromaculatus from Srikulnath et al. [12], and L. agilis from Srikulnath et al. [13].
Mentions: Eighty genes were newly mapped to G. hokouensis chromosomes in the present study, in addition to six Z-linked genes (ATP5A1, GHR, CHD1, DMRT1, RPS6, and ACO1/IREBP) that were mapped in our previous study [39]. We constructed a cytogenetic map for G. hokouensis with 86 functional genes (Figs 3–5), and to the best of our knowledge, this is the first comprehensive cytogenetic map for gekkotan lizards. More than 40 metaphase spreads were observed for each gene, with hybridization efficiencies ranging from approximately 30% to 80%. Chromosome homology between G. hokouensis and the chicken was analyzed using the chicken genome database (http://www.ncbi.nlm.nih.gov/genome/guide/chicken/). Nine genes that were mapped to G. hokouensis chromosome (GHO) 1 were localized to chicken (Gallus gallus) chromosomes (GGA) 3, 12, 13, 16, and 18 (Table 1, Figs 3 & 4). Five genes mapped to GHO2 were localized to GGA5 and GGA7. Seven genes on GHO3 were located on GGA8, GGA20, GGA26, and GGA28. GHO4 (the Z sex chromosome) corresponded to GGAZ, and GHO5 showed homology with GGA4p and GGA23. Five genes on GHO6 were localized to GGA2q, GGA10, and GGA13, and six genes on GHO7 were localized to GGA4q. GHO8 was homologous to GGA2p (Figs 3 & 4). GHO9 showed homology with GGA17, GGA21, and GGA25; GHO10, with GGA14 and GGA24; GHO11, with GGA15; and GHO12, with GGA27. Six genes on GHO13 were located on GGA1q and GGA11. GHO14 was homologous to GGA1p; and GHO15, to GGA6 and GGA9 (Figs 3 & 4). The chromosomal location of KRT8, which has not been determined in the chicken, was mapped to GHO16, and TRIM37 and AMH located on GHO17 were localized to GGA19. No functional genes were mapped to GHO18 and GHO19 in the present study.

Bottom Line: Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG).However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis.These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan; Laboratory of Animal Cytogenetics and Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok, Thailand; Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University (CASTNAR, NRU-KU), Kasetsart University, Bangkok, Thailand.

ABSTRACT
The Hokou gecko (Gekko hokouensis: Gekkonidae, Gekkota, Squamata) has the chromosome number 2n = 38, with no microchromosomes. For molecular cytogenetic characterization of the gekkotan karyotype, we constructed a cytogenetic map for G. hokouensis, which retains the ancestral karyotype of Gekkota, with 86 functional genes, and compared it with cytogenetic maps for four Toxicofera species that have many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) and that for a lacertid species (Lacerta agilis) with only one pair of autosomal microchromosomes. Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG). However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis. These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.

No MeSH data available.