太平洋牡蛎卵母细胞减数分裂中期Ⅰ——染色体交叉配对观察

The Observation on Meiotic Crossover in Oocytes of Pacific Oyster (Crassostrea gigas) at Metaphase During Meiosis Ⅰ

对太平洋牡蛎卵母细胞减数分裂中期同源染色体联会时的聚合形态、聚合体数目以及同源染色体间交叉数目进行了观察与统计。结果表明：在太平洋牡蛎卵母细胞中，聚合体数目变化8～11个不等，以10个二价体为主要存在形式，占82．06％；聚合体形态变化较大，主要有“X”，“V”，“Y”，“∝”，“O”,“8”，棒型及双交叉，其中以“X”型为主要交叉形式。占50．0％；交叉点数目在10-14之间变动，平均为11．2。

In this paper, chromosomes paring configurations, the number of aggregates and chiasma were observed and calculated in Pacific oyster oocytes during meiosis metaphase I . The results show that in diploid oyster eggs, the agreggates ranged from 8 to 11, most in the form of 10 bivalents （82.06%）, but the configurations were highly varied, with the shapes of ＂X＂, ＂V＂, ＂Y＂, ＂co＂, ＂O＂, ＂8＂, rod and double cross observed, of which X-shaped configurations were the main form （50.0 % ）. The numbers of chiasma ranged from 10-14 with an overall mean of 11.2.