Falk R, Jacoby M
Mutat Res. 1975 Sep;29(3):397-406. doi: 10.1016/0027-5107(75)90060-3.
The frequency of induced partial and complete losses of sex chromosomes from spermatozoa of Drosophila melanogaster was determined by mating irradiated males to females heterozygous for an attached-X Y chromosome and for a bb-deficient chromosome. The relative involvement of the X- and Y-chromosomes in partial losses was determined by (a) irradiating males with an X-chromosome centromere marked by a y+ translocated to the short right arm, and a Y-chromosome marked by w+, and (b) comparing the frequencies of fragments recovered from irradiated males with a normal, marked Y-chromosome and from irradiated males and a deleted bb Y-chromsome. 50-80% of the induced losses of sex-chromosomes in rod-X/Y males were partial losses, whereas only 25% of those induced in ring-X/Y males were partial losses. More than 70% of the recovered fragments were of Y-chromosome origin. Fragments recovered from attached-X-Y sons of irradiated males wer checked for the presence of the most proximal euchromatic X-chromosome genes. Most fragments of the rod-X were broken more proximally than bb. In the ring-X there was an excess of fragments broken in the proximal euchromatin. It was concluded that many fragments of the Y-chromosome was due to breaks induced by one-hit events, in both arms of the chromosome that were folded upon themselves. A similar mechanism had been postulated earlier for fragments of the ring-X chromosome.
通过将受辐照的雄性果蝇与具有附着型X Y染色体和bb缺失染色体的杂合雌性果蝇交配，确定了黑腹果蝇精子中性染色体诱导的部分和完全缺失的频率。通过以下方法确定X和Y染色体在部分缺失中的相对参与情况：(a) 用位于短右臂的易位y +标记的X染色体着丝粒和w +标记的Y染色体辐照雄性果蝇；(b) 比较从具有正常标记Y染色体的受辐照雄性果蝇以及从受辐照雄性果蝇和缺失bb的Y染色体中回收的片段频率。在棒状X/Y雄性果蝇中，50 - 80%的性染色体诱导缺失为部分缺失，而在环状X/Y雄性果蝇中，只有25%的诱导缺失为部分缺失。超过70%回收的片段源自Y染色体。检查了从受辐照雄性果蝇的附着型X - Y子代中回收的片段，以确定最近端常染色质X染色体基因的存在情况。棒状X的大多数片段在比bb更靠近近端的位置断裂。在环状X中，近端常染色质中有过多的片段断裂。得出的结论是，Y染色体的许多片段是由于单次打击事件诱导的断裂所致，这些断裂发生在自身折叠的染色体的两条臂上。早期曾针对环状X染色体的片段提出过类似的机制。
