de la Seña C A, Fechheimer N S, Nestor K E
Department of Molecular Genetics, Ohio State University, Columbus 43210.
Cytogenet Cell Genet. 1992;60(2):140-5. doi: 10.1159/000133325.
The Japanese quail was used as an experimental system to detect the effects of genes that affect chromosome behavior and distribution. From a random-bred population, three inbred generations were produced by full-sib matings in 36 families. The expectation from such a breeding scheme was that embryos bearing aberrations induced by recessive mutant genes would cluster within families and recur in particular lineages. Chromosomal aberrations caused by errors during fertilization, cleavage mitosis, and gametogenesis were scored in 2,037 16- to 18-h embryos from 107 families. Comparisons of the observed frequencies among families and lineages and pedigree analysis indicated that four types of chromosome aberrations had a genetic basis: (1) triploidy and triploid chimerism; (2) haploidy and haploid chimerism; (3) diploid/tetraploid mosaicism; and (4) a new aberration, referred to as "atypical mitotic metaphase." Analysis of the sex-chromosome complements of the embryos indicated that triploidy resulted predominantly from diploid ova, haploid cell lines originated from supernumerary sperm nuclei, and tetraploid cell lines resulted from endoreduplication or failure of cytokinesis. Clustering of triploidy in particular lineages was due to dispermy or recurrent suppression of one or both meiotic divisions during oogenesis.
日本鹌鹑被用作实验系统，以检测影响染色体行为和分布的基因的作用。从一个随机繁殖的群体中，通过36个家系的全同胞交配产生了三个近交世代。这种育种方案的预期是，携带由隐性突变基因诱导的畸变的胚胎将在家族中聚集，并在特定谱系中反复出现。在来自107个家系的2037个16至18小时的胚胎中，对受精、卵裂有丝分裂和配子发生过程中错误导致的染色体畸变进行了评分。家族和谱系之间观察频率的比较以及系谱分析表明，四种类型的染色体畸变具有遗传基础：（1）三倍体和三倍体嵌合体；（2）单倍体和单倍体嵌合体；（3）二倍体/四倍体嵌合体；（4）一种新的畸变，称为“非典型有丝分裂中期”。对胚胎性染色体组成的分析表明，三倍体主要由二倍体卵子产生，单倍体细胞系起源于多余的精核，四倍体细胞系由核内复制或胞质分裂失败产生。特定谱系中三倍体的聚集是由于双精受精或卵子发生过程中一个或两个减数分裂的反复抑制。
