A Possible Alternative to the Hypothesis of Selective Fertilization in Sciara

Abstract

Although the evidence strongly indicates the presence of completely selective fertilization in Sciara, it is suggested that judgment be reserved on this point until the peculiar behavior of the "precocious" chromosome during the 2nd spermatocyte division is understood. Apparently each sperm receives 2 sister halves of this chromosome, and it is suggested that the. peculiar mitotic behavior which brings this about may alter one of the elements. If the "precocious" chromosome is a sex chromosome the alteration might serve to transform an X into a Y.