In: Biology
What is the outcome of nondisjunction in meiosis I of an organism with ploidy 2n=2?
A - one quarter of the resultant gametes will be devoid of all chromosomes
B - half of the resulting gametes will contain non-sister chromatids
C - half of the resulting gametes will contain sister chromatids
D - half of the resulting gametes will be trisomic
E - half of the resulting gametes will be haploid
The given species is in diploid condition contains total number of chromosome 2.
Nondisjunction means failure to separate the chromosome during cell division. It may happen in three cases during meiosis I, meiosis II and mitosis.
Here the given case is of meiosis I. When the chromosoms are arranged at metaphase plate after dna replication that happened earlier, the unequal division or non disjunction results in the formation of two cells; one of the cell contain all single set of pair of homologous chromosome while other one cell has devoid of any chromosome.
Again, when meiosis II happens during gamete formation; the cell that devoid of any chromosome results in two gamete production that also devoid of chromosomes. But, in other situation, the cell containing pair of homologous chromosome devide in two gametes separating their homologous chromosome. Hence, the two cells contain sister chromatids.
Overall, it is clear that half of the gamete is devoid of chromosome and other balf contains the sister chromatids.
So, correct option is C.