Germ line-restricted supernumerary (B) chromosomes in Eptatretus okinoseanus

Autor:	Y. Nakai, Souichirou Kubota, Sei-ichi Kohno, Makoto Kuro-o
Rok vydání:	1992
Předmět:	Genetics medicine.medical_specialty B chromosome Somatic cell Cytogenetics Chromosome Aneuploidy Spermatocyte Biology medicine.disease Molecular biology medicine.anatomical_structure Meiosis medicine Molecular Biology Small supernumerary marker chromosome Genetics (clinical)
Zdroj:	Cytogenetic and Genome Research. 60:224-228
ISSN:	1424-859X 1424-8581
DOI:	10.1159/000133345
Popis:	Cytogenetic studies were performed on two types of Japanese hagfish (Eptatretus okinoseanus) that eliminate about 45% (type A) and 55% (type B) of their DNA from presumptive somatic cells during the differentiation of somatic cells. The observations revealed inter- and intraindividual variations in the number of chromosomes in germ cells of both types of hagfishes. Although the modal number of chromosomes in the germ cells was 54 in both types, the percentage of cells with the modal number was rather low (38.6% [51/132] in five specimens of type A and 22.7% [25/110] in eight specimens of type B). In addition, one of seven type B specimens clearly had a modal number of 62 chromosomes. Another specimen of type B had a bimodal distribution of chromosome numbers, with peaks of 54 and 59 chromosomes. The observation of interindividual variations was supported by data on the amount of DNA in germ cells of type B specimens. However, these variations were rarely observed in somatic cells. These results suggest that supernumerary (B) chromosomes are maintained in germ cells and are eliminated together with some other chromosomes and/or chromatin from somatic cells.
Databáze:	OpenAIRE
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