Question

The number of linkage group in a particular plants species is equal to the

• A. Gametic chromosome number
• B. Number genes present in that species
• C. Half the number of genes present in that species
• D. Somatic chromosome number of that species

Hint:

Always remember: Number of Linkage Groups = Haploid Chromosome Number (\(n\)) = Gametic Chromosome Number.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A linkage group refers to a set of genes located on the same physical chromosome that tend to be inherited together during meiosis.

Step 2: Detailed Explanation:
Because genes located on the same physical chromosome are physically linked, the total number of linkage groups in an organism corresponds directly to its unique chromosome types.
In diploid organisms, chromosomes exist as homologous pairs.
Each pair contains the same sequence of genes, and thus represents a single linkage group.
Therefore, the total number of linkage groups is equal to the number of chromosomes in a single haploid set, which is the gametic chromosome number (\(n\)).
For example, Pisum sativum (pea) has a somatic chromosome number of \(2n = 14\), giving it exactly 7 linkage groups.
Humans have a somatic number of \(2n = 46\) (\(22\) pairs of autosomes and \(2\) sex chromosomes), resulting in \(24\) distinct linkage groups in males.

Step 3: Final Answer:
The number of linkage groups is equal to the gametic chromosome number.