172 General Biology 



forming sperm would possess ten and the other eleven chromosomes. 

 The regular somatic number of chromosomes in such an organism 

 would be twenty-two. The egg will, therefore, regularly divide and 

 throw off eleven to obtain the haploid number. Those eggs, which are 

 then fertilized by a sperm containing ten chromosomes, become males 

 (as the diploid number in such a case would again be twenty-one) and 

 those eggs fertilized by a sperm containing eleven would possess the 

 full somatic number of twenty-two chromosomes and become a female. 



This means that in those cases where there are X-chromosomes, 

 the odd chromosome never pairs in the maturation division with another 

 chromosome, nor does it produce a tetrad. It simply passes undivided 

 to the daughter sperm. 



References : 



L. Doncaster, "An Introduction to the Study of Cytology." 



W. E. Agar, "Cytology." 



W. E. Castle, "Genetics and Eugenics." 



East and Jones, "Inbreeding and Outbreeding." 



