Synaptonemal complex analysis of B-chromosome behavior in meiotic prophase I in the East-Asiatic mouse Apodemus peninsulae (Muridae, Rodentia).
The mitotic and meiotic chromosomes of four male East-Asiatic mice, Apodemus peninsulae, having three to seven chromosomes in addition to the standard karyotype (2n = 48), were investigated. B-chromosomes were represented by medium-sized metacentric and dotlike chromosomes. Mosaicism of bone marrow cells due to a numerical variation of accessory chromosomes was established for the males examined. Capacity of B-chromosomes to form axial elements and synaptonemal complexes in meiotic prophase I was revealed by electron microscopy. The occurrence of univalents of different morphology, bivalents, and multivalents, corresponding to B-chromosomes, was demonstrated. An increase in the number of B-chromosomes was found in spermatocytes at zygotene-pachytene relative to the number in bone marrow cells, which may be evidence of B-chromosome accumulation in the germ cell line of the East-Asiatic mouse.
Kolomiets
O L
OL
N.I. Vavilov Institute of General Genetics Academy of Sciences of the USSR., Moscow.
Borbiev
T E
TE
Safronova
L D
LD
Borisov
Y M
YM
Bogdanov
Y F
YF
D000818:Animals; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D008854:Microscopy, Electron; D008938:Mitosis; D009115:Muridae / Q000235:genetics*; D011418:Prophase; D013090:Spermatocytes / Q000648:ultrastructure*; D013573:Synaptonemal Complex