Question

In which one of the following combinations (1-4)
of the number of the chromosomes is the present
day hexaploid whaet correctly represented
Combination (1) (2) (3) (4)
Monosomic 21 7 21 41
Haploid 28 28 7 21
Nullisomic 42 40 42 40
Trisomic 43 42 43 43 please explain in detail​

Answer 1

Answer:

Option :D

Explanation:

Wheat, Triticum aestivum, has basic chromosome number is n = 7; thus the hexaploid species (Triticum aestivum) have 6n = 42.  Haploid chromosome number is the one present in gametes of that organism; gametes contain half the chromosomes of the somatic cells. Thus, haploid chromosome number of hexaploid wheat is 21. This makes options A, B and C incorrect. Nullisomy is absence of one complete pair of homologous chromosomes (2n-2). Thus, nullisomic hexaploid wheat is 42-2 = 40. This makes options A and C incorrect. Monosomy is absence of a single chromosome from a diploid cell (2n-1); therefore, monosomic hexapoid wheat has 42-1 = 41 chromosomes. A diploid cell with an extra chromosome is trisomic (2n+1); thus, total number of chromosomes in a trisomic hexaploid wheat is 42+1 = 43. This makes option D correct answer.