Question

Species X is diploid with a chromosome complement of AABBCCDD. A related species, Y, has chromosomes MMNNOOPPQQ. Please indicate how you obtain your answers.

a. How many chromosomes does Species X carry in each somatic cell?

b. What is the ploidy of normal somatic cells of Species X?

c. How many chromosomes does Species Y carry in each somatic cell?

d. What is the ploidy of normal somatic cells of Species Y?

e. How many chromosomes would an amphidiploid of Species X and Y hold in each cell?

f. What is the chromosome complement of the amphidiploid in the question above?

g. What types of chromosomal mutations do individual organisms with the following sets of chromosomes have? Please include the relevant species.

1. AAABBCCDD

2. MMNNOOOOPPQQ

3. AAABBBCCCDDD

4. AABBCDD

5. AABBCCDDMNOPQ

6. ABCDMMNNOOPPQQ

Answer 1

The two species X nad Y are said to be diploid , and their chromosome comlpements are given with.

a) Species X will carry 8 chromosomes in each somatic cell. Because, the specie is said to be diploid, and the chromosome complement is given as AABBCCDD. That is 2 copies of all A,B, C and D chromosomes are there. Since the somatic cell is diploid in nature, a total of 8 chromosomes will be present per cell.

b) Somatic cells will be diploid in nature. The the somatic cells of species X wil be diploid,with 2n= 8. This is because a total of 8 chromosomes (4 pairs) are there.

c) Just like in the case of species X, species Y is also given with the chromosome complement. From the data, it is clear that species Y carries a total of 10 chromosomes, 2 copies of chromosomes M, N, O, P and Q. Here also, the somatic cell will be diplod , thus each somatic cell will carry 10 chromosomes.

d) The normal somatic cells of species Y will be diploid. That is 2n =10. Because there are 5 chromosome pairs are seen. The somatic cell will always carry diploid number of chromosomes.

e) Amphidiploid is originated by two different diploid species. Amphidiploid will carry diploid sets of chromosomes from both the diploid species, from which it was formed. Here, two diploid species,X and Y are forming an amphidiploid. Thus, the resultant species will carry two diploid sets of chromosomes in its cell, one diploid set from species X and other diploid set from species Y. There are a total of 8 chromosomes in the species X and a total of 10 chromosomes in species Y. Thus the amphidiploid of species X and Y will carry a total of 18 chromosomes in its cell ( 8+10). That is 2n= 18.

f) the chromosome complement of amphidiploid will be AABBCCDDMMNNOOPPQQ. Because species X have chromosome complement AABBCCDD and species Y have the chromosome complement MMNNOOPPQQ. Thus the amphidiploid produced will carry chromosomes of both the species.

g) 1- Trisomy in species X. In trisomy an extra copy of a chromosome will be seen. Here extra copy of chromosome A is produced.

2. Tetrasomy of species Y. In tetrasomy 2 extra copies of a chromosome will be produced. Thus a total of 4 copies of that chromosome will be there. Here tetrasomy in the chromosome "O" is present.

3. Triploidy of species X. It is the type of polyploidy where an extra copy of all the chromosomes are produced in a diploid oraganism. Thus a total of 3 copies of each chromosomes will be produced.

4.Monosomy in species X. In monosomy, one copy of chromosome will be missing from a chromosome pair. Here only one copy of chromosome "C' is seen. Its pair is missing.