Question

Question 7 a) A Drosophila species is diploid (2n8), with letters H through J corresponding to four different chromosomes. In this species, how would you categorize the following genomes? For full credit include the ploidy formula and the technical name for the each (4 points) a. HH II J KK b. HH III JJ KK c. HHHH IIII JJJJ KKKK d. HH II JJ KK b) What is the difference between trisomy and triploid and which is likely show the most deleterious effects of it chromosomal abnormality? (2 points) c) Which is worse, non-disjunction during Meiosis I or non-disjunction during Meiosis II. and why? (2 points) d) In terms of whole chromosome deletion or duplication, explain why the size of the chromosome matters? (2 points) 3.5581

Answer 1

7. b) The difference between trisomy and triploid is given below-

Trisomy is the addition of an extra chromosome due to chromosomal aberration whereas triploid is the set of three chromosome present in an organism (e.g. seedless watermelon).

Chromosome number in trisomy is denoted as 2N + 1 , where N is the number of chromosome.

Chromosome number in triploid is denoted as 3N, where N is the number of chromosome.

Trisomy shows most deleterious effect. It is the source of diseases like Down's Syndrome, Edward Syndrome, Klinefelter syndrome,etc.

c. Out of non-disjunction during Meiosis I and non-disjunction during Meiosis II, non-disjunction during Meiosis I is worse because if produces two types of gametes - (n+1) and (n-1), both of which are abnormal. In case of non-disjunction in Meiosis II, three types of gametes are produced- n, (n+1), (n-1), out of which at least the 'n' type gamete is normal type.