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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.


Related in: MedlinePlus

Schematic representation for the process of chromosomal rearrangements that occurred among Gekko hokouensis chromosomes (GHO) 1, 2, and Z, Lacerta agilis chromosomes (LAG) 1 and 3, and Leiolepis reevesii rubritaeniata chromosomes (LRE) 1 and 2.The diagram schematically summarizes the occurrences of LRE1, GHO1, LAG1, and LAG3 (a); LRE2, GHO1, and GHOZ (b); and LAG1 and GHO2 (c). LAG3 in (a) and GHOZ in (b) are inverted to facilitate comparison. Chromosomal locations of the genes are shown to the right of the chromosomes by using arrowheads. Homologous chromosomes and/or chromosome segments are shown using the same color. Arrows indicate the directions of the chromosomal rearrangements.
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pone.0134829.g007: Schematic representation for the process of chromosomal rearrangements that occurred among Gekko hokouensis chromosomes (GHO) 1, 2, and Z, Lacerta agilis chromosomes (LAG) 1 and 3, and Leiolepis reevesii rubritaeniata chromosomes (LRE) 1 and 2.The diagram schematically summarizes the occurrences of LRE1, GHO1, LAG1, and LAG3 (a); LRE2, GHO1, and GHOZ (b); and LAG1 and GHO2 (c). LAG3 in (a) and GHOZ in (b) are inverted to facilitate comparison. Chromosomal locations of the genes are shown to the right of the chromosomes by using arrowheads. Homologous chromosomes and/or chromosome segments are shown using the same color. Arrows indicate the directions of the chromosomal rearrangements.

Mentions: However, two of the largest chromosome pairs (GHO1 and GHO2) are bi-armed chromosomes. GHO1p is homologous to LRE1p and LAG3; however, the gene order of GHO1p is different from that of LRE1p and LAG3. Considering the phylogenetic positions of Gekkota and Lacerta, it is most likely that LRE1 resulted from centric fusion between LAG1 and the acrocentric proto-GHO1p, followed by paracentric inversion in LRE1p. Proto-GHO1p may have fused with the acrocentric proto-GHO1q in G. hokouensis, leading to the present bi-armed GHO1. LAG3 may have been derived from proto-GHO1p by a large paracentric inversion (Fig 7A). GHOZ is homologous to LRE2p and GHO1q, to LRE2q (Fig 7B). LRE2 was probably derived from centric fusion between the acrocentric proto-GHOZ and proto-GHO1q, followed by paracentric inversions in LRE2q, based on the evidence of chromosome homology with the other three Toxicofera species (Fig 5) and their phylogenetic relationships [6].


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)

Schematic representation for the process of chromosomal rearrangements that occurred among Gekko hokouensis chromosomes (GHO) 1, 2, and Z, Lacerta agilis chromosomes (LAG) 1 and 3, and Leiolepis reevesii rubritaeniata chromosomes (LRE) 1 and 2.The diagram schematically summarizes the occurrences of LRE1, GHO1, LAG1, and LAG3 (a); LRE2, GHO1, and GHOZ (b); and LAG1 and GHO2 (c). LAG3 in (a) and GHOZ in (b) are inverted to facilitate comparison. Chromosomal locations of the genes are shown to the right of the chromosomes by using arrowheads. Homologous chromosomes and/or chromosome segments are shown using the same color. Arrows indicate the directions of the chromosomal rearrangements.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0134829.g007: Schematic representation for the process of chromosomal rearrangements that occurred among Gekko hokouensis chromosomes (GHO) 1, 2, and Z, Lacerta agilis chromosomes (LAG) 1 and 3, and Leiolepis reevesii rubritaeniata chromosomes (LRE) 1 and 2.The diagram schematically summarizes the occurrences of LRE1, GHO1, LAG1, and LAG3 (a); LRE2, GHO1, and GHOZ (b); and LAG1 and GHO2 (c). LAG3 in (a) and GHOZ in (b) are inverted to facilitate comparison. Chromosomal locations of the genes are shown to the right of the chromosomes by using arrowheads. Homologous chromosomes and/or chromosome segments are shown using the same color. Arrows indicate the directions of the chromosomal rearrangements.
Mentions: However, two of the largest chromosome pairs (GHO1 and GHO2) are bi-armed chromosomes. GHO1p is homologous to LRE1p and LAG3; however, the gene order of GHO1p is different from that of LRE1p and LAG3. Considering the phylogenetic positions of Gekkota and Lacerta, it is most likely that LRE1 resulted from centric fusion between LAG1 and the acrocentric proto-GHO1p, followed by paracentric inversion in LRE1p. Proto-GHO1p may have fused with the acrocentric proto-GHO1q in G. hokouensis, leading to the present bi-armed GHO1. LAG3 may have been derived from proto-GHO1p by a large paracentric inversion (Fig 7A). GHOZ is homologous to LRE2p and GHO1q, to LRE2q (Fig 7B). LRE2 was probably derived from centric fusion between the acrocentric proto-GHOZ and proto-GHO1q, followed by paracentric inversions in LRE2q, based on the evidence of chromosome homology with the other three Toxicofera species (Fig 5) and their phylogenetic relationships [6].

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.


Related in: MedlinePlus