Complex structure of B-chromosomes in two mammalian species: Apodemus peninsulae (Rodentia) and Nyctereutes procyonoides (Carnivora).
B-chromosomes (Bs) of two mammalian species, raccoon dog (Nyctereutesprocyonoides, Carnivora) and Asian wood mouse (Apodemus peninsulae, Rodentia) were investigated using chromosome segment microdissection and double-colour FISH. In the raccoon dog, all B-chromosomes showed homology with each other but not with the A-chromosomes. Two segment-specific probes (from proximal and distal parts of B) have been localized in corresponding chromosome parts, with significant variation in their sizes. In Asian wood mice, two types of B-specific chromatin were revealed--B1 and B2. Most Bs were either B1 or B2 specific; furthermore, some Bs were found to be composed of both types of chromatin. B-chromosome-specific libraries of A. peninsulae contain sequences homologous to the heterochromatic regions of sex and some A-chromosomes and dispersed repeated sequences. B1-specific probes gave signals on sex chromosomes of Apodemus speciosus and Apodemus agrarius. The origin and evolution of B-chromosomes in mammals are discussed.
Trifonov
V A
VA
The Institute of Cytology and Genetics, Novosibirsk, Russia. vlad@bionet.nsc.ru
Perelman
P L
PL
Kawada
S I
SI
Iwasa
M A
MA
Oda
S I
SI
Graphodatsky
A S
AS
D000818:Animals; D002335:Carnivora / Q000235:genetics*; D002869:Chromosome Aberrations; D002875:Chromosomes; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D009115:Muridae / Q000235:genetics*; D012730:Sex Chromosomes; D016615:Telomere / Q000235:genetics