Question

An allotetraploid plant with 2n = 30 is backcrossed to one of its progenitor species that has an n = 8. A sterile progeny is produced.

a. What are the chromosome numbers for each of the two progenitor species that formed the original allotetraploid plant?

b. How many chromosomes will the sterile progeny possess?

Answer 1

A) Given,

Chromosome number of allotertraploid plant (2n)= 30

Haploid chromosome number of one of its progenitor species (n) =8

Diploid chromosomes content of this species= 2n= 2X8= 16

Diploid chromosomes number of other progenitor species = (2n)= 30- 16 = 14

Haploid chromosome number of other progenitor species = n = 14/2 =7

B) Haploid chromosome number of allotertraploid plant = 15

Haploid chromosome content of one of progenitor plant = 8

Chromosome number of resulting plant = Haploid content of the allotertraploid plant +haploid content of one of the progenitor plant= 15+8=23