The evidence that crossing over occurs at four stranded stage and not at two stranded stage of the chromosomes, comes from

Options

A. 2 : 2 : 2 : 2 arrangement of ascospores in Neurospora
B. 4 : 4 arrangement of ascospores in Neurospora
C. Studies of meiosis in maize
D. Studies on linkage maps of chromosomes in Drosophila

Answer

A

Explanation

In Neurospora Eight oospores are arranged in a linear show, the arrangement of as oospores in the ration of 2 black : 2 white : 2 black : 2 white show that crossing over occurs at 4 – 5 stranded stage giving alternation of black and white asoospores.