Diploid nuclei of the ascomycete Neurospora crassa contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores. How many chromosomes would a single ascospore nucleus of this species contain?
A) 7 chromosomes
B) 14 chromosomes
C) 21 chromosomes
D) 28 chromosomes

Question

Quizplus · Accepted Answer

Neurospora crassa is haploid for most of its life cycle, meaning its cells typically contain a single set of chromosomes. The diploid phase is brief and involves the fusion of two haploid nuclei to form a diploid nucleus with 14 chromosomes. Following meiosis, the chromosome number is halved, resulting in cells with 7 chromosomes. The subsequent round of mitosis does not change the chromosome number, so each ascospore nucleus contains 7 chromosomes.

Diploid Nuclei of the Ascomycete Neurospora Crassa Contain 14 Chromosomes