Prakash K L, Aswathanarayana N V
J Hered. 1977 Mar-Apr;68(2):126-8. doi: 10.1093/oxfordjournals.jhered.a108787.
The south Indian black rat, Rattus r. rufescens (Gray) has a diploid number of 38 chromosomes. A random sample from Hinakal (Mysore, S.W. India) revealed the presence of rats with aneuploid chromosome numbers, viz. 2n = 37, 39, 40, and 42. The 37-chromosome individual was a female and possessed the XO constitution. The diploid numbers higher than 38 were due to the presence of supernumerary (B) chromosomes. The origin and consequences of the XO condition in Rattus r. rufescens and other mammals is discussed.
南印度黑鼠（Rattus r. rufescens，格雷）的二倍体染色体数为38条。从希纳卡尔（印度西南部迈索尔）采集的随机样本显示存在非整倍体染色体数的大鼠，即2n = 37、39、40和42。具有37条染色体的个体为雌性，具有XO核型。高于38的二倍体数是由于存在超数（B）染色体。本文讨论了南印度黑鼠及其他哺乳动物中XO核型的起源和后果。
