Karyological relationships between the Cryptobranchid salamanders

Morescalchi, A.; Odierna, Gaëtano; Olmo, Ettore

doi:10.1007/bf01934008

Cited by 22 publications

(18 citation statements)

References 8 publications

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“…In the other extreme, the Apostolepis genus presents the highest diploid chromosome number so far found in the suborder Serpentes and the highest number of microchromosomes, some of them very small (Beçak et al 2003). Besides most reptilian orders, microchromosomes are also found in some primitive amphibians, including the families Cryptobranchidae and Hynobiidae, at 2n=56-66 with 14-19 pairs of microchromosomes and most avian (Morescalchi et al 1977(Morescalchi et al , 1979. Some retiles and all Crocodylia lack microchromosomes (King et al 1986); a puzzle given that the crocodilian lineage is, phylogenetically, the closest to birds.…”

Section: Resultsmentioning

confidence: 99%

First Cytogenetic Study of Puff-Faced Water Snake, Homalopsis buccata (Squamata, Colubridae) by Conventional Staining, Ag-NOR Banding and GTG-Banding Techniques

et al. 2013

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SummaryThe first cytogenetics of the puff-faced water snake (Homalopsis buccata) from Khon Kaen Province, Thailand was obtained from the present study. Mitotic chromosome was prepared directly from the spleens of specimens after in vivo colchicines treatment. The metaphase spreads were performed on microscopic slides and air-dried. Conventional staining, Ag-NOR banding, and GTG-banding techniques were applied to stain the chromosome with Giemsa s solution. Results showed that the number of diploid chromosome was 2n=36, while the fundamental number (NF) was 52 in both males and females. The types of macrochromosome were four large metacentric, two medium metacentric, six small metacentric, and two small acrocentric chromosome, and 20 microchromosomes. It was found that nucleolar organizer regions (NORs, the representative of chromosome marker) locate on the long arms near centromeres of a pair of microchromosomes, pair 15. The Z chromosome was a small metacentric chromosome, while the W chromosome was a small submetacentric chromosome. From the GTG-banding technique, it was found that each chromosome pairs could be clearly differentiated and the numbers of bands in the H. buccata was 109. The karyotype formula is as follows:2n (

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Section: Resultsmentioning

confidence: 99%

First Cytogenetic Study of Puff-Faced Water Snake, Homalopsis buccata (Squamata, Colubridae) by Conventional Staining, Ag-NOR Banding and GTG-Banding Techniques

et al. 2013

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“…For some reptiles and primitive amphibians the presence of microchromosomes would suggest few intra-and interchromosomal rearrangements reached fixation. This is supported by the conservative nature of many reptilian and primitive amphibian karyotypes (Morescalchi et al, 1977a(Morescalchi et al, , 1977b(Morescalchi et al, , 1979Mühlmann-Diaz, 2001). …”

Section: A "Fission-fusion Model" Of Microchromosome Evolutionmentioning

confidence: 96%

“…Besides all avian orders, microchromosomes are also found in some primitive amphibians (Cryptobranchidae and Hynobiidae, 2n = 56-66, with 14-19 pairs of microchromosomes, Morescalchi et al, 1977bMorescalchi et al, , 1979 and most reptiles (snakes 2n = 36, with about 20 pairs of microchromosomes, Mengden and Stock, 1980). Some reptiles and all Crocodylia lack microchromosomes (King et al, 1986); a puzzle given that the crocodilian lineage is phylogenetically the closest to birds.…”

Section: Microchromosomes Are Present In Birds and Many Vertebratesmentioning

confidence: 99%

“…Microchromosomes are characteristic of all avian and many reptilian karyotypes, with the notable exception of the Crocodylia, a lineage phylogenetically closest to birds with a common ancestor 254 million years ago (Mya) (Janke and Arnason, 1997). Microchromosomes are also present in the karyotypes of many primitive vertebrates (Ohno et al, 1969;Morescalchi et al, 1977aMorescalchi et al, , 1977bMorescalchi et al, , 1979. These observations have led to the hypothesis that avian microchromosomes may represent archaic linkage groups of ancestral vertebrates (Tegelström and Ryttman, 1981;Jones et al, 1997;Fillon, 1998).…”

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confidence: 99%

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Origin and evolution of avian microchromosomes

Burt¹

2002

Cytogenet Genome Res

219

262

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The origin of avian microchromosomes has long been the subject of much speculation and debate. Microchromosomes are a universal characteristic of all avian species and many reptilian karyotypes. The typical avian karyotype contains about 40 pairs of chromosomes and usually 30 pairs of small to tiny microchromosomes. This characteristic karyotype probably evolved 100–250 million years ago. Once the microchromosomes were thought to be a non-essential component of the avian genome. Recent work has shown that even though these chromosomes represent only 25% of the genome; they encode 50% of the genes. Contrary to popular belief, microchromosomes are present in a wide range of vertebrate classes, spanning 400–450 million years of evolutionary history. In this paper, comparative gene mapping between the genomes of chicken, human, mouse and zebrafish, has been used to investigate the origin and evolution of avian microchromosomes during this period. This analysis reveals evidence for four ancient syntenies conserved in fish, birds and mammals for over 400 million years. More than half, if not all, microchromosomes may represent ancestral syntenies and at least ten avian microchromosomes are the product of chromosome fission. Birds have one of the smallest genomes of any terrestrial vertebrate. This is likely to be the product of an evolutionary process that minimizes the DNA content (mostly through the number of repeats) and maximizes the recombination rate of microchromosomes. Through this process the properties (GC content, DNA and repeat content, gene density and recombination rate) of microchromosomes and macrochromosomes have diverged to create distinct chromosome types. An ancestral genome for birds likely had a small genome, low in repeats and a karyotype with microchromosomes. A “Fission–Fusion Model” of microchromosome evolution based on chromosome rearrangement and minimization of repeat content is discussed.

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“…Contrary to popular belief, microchromosomes are present in a wide range of vertebrate classes, spanning 400-450 million years of evolutionary history (Burt 2002). Microchromosomes are also present in the karyotype of many primitive vertebrates (Ohno et al 1969, Morescalchi et al 1977a, 1977b, 1979, Burt 2002). These observations have led to the hypothesis that avian microchronosomes may represent an archaic linkage group of ancestral vertebrates (Tegelström and Ryttman 1981, Jones et al 1997, Fillon 1998.…”

Section: Resultsmentioning

confidence: 90%

First Karyological Analysis of Black the Crowned Crane (Balearica pavonina) and the Scaly-Breasted Munia (Lonchura punctulata)

et al. 2013

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SummaryThis research was the first karyological analysis of the black crowned crane (Balearica pavonina) and the scaly-breasted munia (Lonchura punctulata). Two specimens of B. pavonina (one male and one female) and two specimens of L. punctulata (one male and one female) were obtained from Nakhon Ratchasima Zoo, Thailand. After using the standard peripheral blood lymphocyte culture method at 41 C for 72 h in the presence of colchicine, the metaphase spreads were performed on microscopic slides and air-dried. A conventional staining technique was applied to stain the chromosomes. The results showed that the diploid chromosome number of B. pavonina is 2n=80. The chromosomes have two sizes; 11 pairs of macrochromosomes and 29 pairs of microchromosomes were observed. The macrochromosomes consist of 14 metacentric, 6 submetacentric, and sex chromosomes. The Z chromosome is a medium metacentric chromosome and the W chromosome is a small metacentric chromosome. The diploid chromosome number of L. punctulata is 2n=72. The chromosomes have two sizes; 10 pairs of macrochromosomes and 25 pairs of microchromosomes were observed. The macrochromosomes consist of 2 metacentric, 4 submetacentric, 2 acrocentric, 10 telocentric, and sex chromosomes. The Z chromosome is a small metacentric chromosome and the W chromosome is the smallest metacentric chromosome.

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Karyological relationships between the Cryptobranchid salamanders

Cited by 22 publications

References 8 publications

First Cytogenetic Study of Puff-Faced Water Snake, <i>Homalopsis buccata</i> (Squamata, Colubridae) by Conventional Staining, Ag-NOR Banding and GTG-Banding Techniques

First Cytogenetic Study of Puff-Faced Water Snake, <i>Homalopsis buccata</i> (Squamata, Colubridae) by Conventional Staining, Ag-NOR Banding and GTG-Banding Techniques

Origin and evolution of avian microchromosomes

First Karyological Analysis of Black the Crowned Crane (<i>Balearica pavonina</i>) and the Scaly-Breasted Munia (<i>Lonchura punctulata</i>)

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