Question

The primrose, Primula kewensis, has 36 chromosomes that are similar in appearance to the chromosomes in two related species, \(P .\) floribunda $(2 n=18)\( and \)P\(. verticillata \)(2 n=18) .$ How could P. kewensis arise from these species? How would you describe \(P\) kewensis in genetic terms?

Short answer

Describe P. kewensis in genetic terms. Answer: Primula kewensis likely arose as an allopolyploid species, where a hybridization event between P. floribunda and P. verticillata, both having 18 chromosomes, resulted in the formation of P. kewensis, having 36 chromosomes. Each parent species contributed their entire set of chromosomes to create P. kewensis.

Step-by-step solution

Identify the chromosome numbers of the species

We are given three species and their respective chromosome numbers: - Primula kewensis: \(2n = 36\) - P. floribunda: \(2n = 18\) - P. verticillata: \(2n = 18\)

Analyze the relationship between the chromosome numbers

To determine how P. kewensis arose from P. floribunda and P. verticillata, we should investigate the relationship between their chromosome numbers. It can be observed that the number of chromosomes of P. kewensis (36) is double the number of chromosomes of P. floribunda (18) and P. verticillata (18).

Hypothesize the genetic mechanism involved

Since the P. kewensis has double the number of chromosomes of P. floribunda and P. verticillata, it suggests that P. kewensis could be an allopolyploid species. Allopolyploid species arise from a hybridization event between two different species, followed by a genome duplication, in which the chromosomes from both the parent species are combined into a new species. In this scenario, both P. floribunda and P. verticillata could have contributed their entire set of chromosomes to create P. kewensis.

Describe P. kewensis in genetic terms

P. kewensis can be described as an allopolyploid species, with a diploid chromosome number of 36, which likely arose from a hybridization event between P. floribunda and P. verticillata, where both species contributed their chromosomes to the formation of P. kewensis.