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Inbreeding Ratio and Genetic Relationships among Strains of the Western Clawed Frog, Xenopus tropicalis.

Igawa T, Watanabe A, Suzuki A, Kashiwagi A, Kashiwagi K, Noble A, Guille M, Simpson DE, Horb ME, Fujii T, Sumida M - PLoS ONE (2015)

Bottom Line: It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s.Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains.Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts.

View Article: PubMed Central - PubMed

Affiliation: Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.

ABSTRACT
The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts.

No MeSH data available.


Related in: MedlinePlus

General pedigree chart of X. tropicalis strains.Frogs facing left represent the Ivory Coast strain and those facing right are Nigerian strains. Frogs colored black indicate strains used in this study. The arrows and figures next to frogs indicate transportation of animals and the years when those were held (if there is a record).
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pone.0133963.g001: General pedigree chart of X. tropicalis strains.Frogs facing left represent the Ivory Coast strain and those facing right are Nigerian strains. Frogs colored black indicate strains used in this study. The arrows and figures next to frogs indicate transportation of animals and the years when those were held (if there is a record).

Mentions: As mentioned above, the two major strains of X. tropicalis are known as Nigerian and Ivory Coast. The three Nigerian strains were transferred to IAB from the Grainger lab and the Harland lab by way of the University of Tokyo and the Nara Institute of Science and Technology (NAIST), while Ivory Coast was obtained directly from the Université de Genève. Although IAB also maintains an Asashima strain, it was not used in this study because it is genetically far apart and probably a different species or subspecies [13]. For comparison, we also investigated one Nigerian and two Ivory Coast stocks from the European Xenopus Resource Centre (EXRC), two Nigerian stocks from the The Wellcome Trust / Cancer Research UK Gurdon Institute (Gurdon Inst.) in the UK, and two Nigerian and one Ivory Coast stock from National Xenopus Resource (NXR) in the US. General pedigree information is summarized in Fig 1. Ten tadpoles from each colony were used for subsequent experiments and analyses, except for Ivory Coast from EXRC from which only two tadpoles were obtained and thus used only in the analysis based on mitochondrial genes.


Inbreeding Ratio and Genetic Relationships among Strains of the Western Clawed Frog, Xenopus tropicalis.

Igawa T, Watanabe A, Suzuki A, Kashiwagi A, Kashiwagi K, Noble A, Guille M, Simpson DE, Horb ME, Fujii T, Sumida M - PLoS ONE (2015)

General pedigree chart of X. tropicalis strains.Frogs facing left represent the Ivory Coast strain and those facing right are Nigerian strains. Frogs colored black indicate strains used in this study. The arrows and figures next to frogs indicate transportation of animals and the years when those were held (if there is a record).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519292&req=5

pone.0133963.g001: General pedigree chart of X. tropicalis strains.Frogs facing left represent the Ivory Coast strain and those facing right are Nigerian strains. Frogs colored black indicate strains used in this study. The arrows and figures next to frogs indicate transportation of animals and the years when those were held (if there is a record).
Mentions: As mentioned above, the two major strains of X. tropicalis are known as Nigerian and Ivory Coast. The three Nigerian strains were transferred to IAB from the Grainger lab and the Harland lab by way of the University of Tokyo and the Nara Institute of Science and Technology (NAIST), while Ivory Coast was obtained directly from the Université de Genève. Although IAB also maintains an Asashima strain, it was not used in this study because it is genetically far apart and probably a different species or subspecies [13]. For comparison, we also investigated one Nigerian and two Ivory Coast stocks from the European Xenopus Resource Centre (EXRC), two Nigerian stocks from the The Wellcome Trust / Cancer Research UK Gurdon Institute (Gurdon Inst.) in the UK, and two Nigerian and one Ivory Coast stock from National Xenopus Resource (NXR) in the US. General pedigree information is summarized in Fig 1. Ten tadpoles from each colony were used for subsequent experiments and analyses, except for Ivory Coast from EXRC from which only two tadpoles were obtained and thus used only in the analysis based on mitochondrial genes.

Bottom Line: It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s.Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains.Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts.

View Article: PubMed Central - PubMed

Affiliation: Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.

ABSTRACT
The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts.

No MeSH data available.


Related in: MedlinePlus