Q.86 A particular species is found to have 𝟐𝒏 = 𝟏𝟔 chromosomes. The number of linkage groups in this
species will be ____
Linkage groups represent sets of genes inherited together on the same chromosome, equaling the haploid chromosome number (n) in diploid organisms. For a species with 2n=16 chromosomes, the number of linkage groups is 8.
Correct Answer
The number of linkage groups is 8. This follows from the diploid number 2n=16, where n=8 defines the distinct chromosome types in gametes, each forming one linkage group.
Key Concept Explained
Linkage groups correspond to individual chromosomes because genes on the same chromosome tend to be inherited together unless separated by crossing over. In this species, somatic cells have 16 chromosomes (8 homologous pairs), but gametes carry 8 chromosomes—one from each pair—thus 8 linkage groups. This holds for most sexually reproducing diploid species like plants or animals.
Options Analysis
Typical multiple-choice options for this question include 16, 8, 4, or “impossible to tell.” Here’s why each is right or wrong:
| Option | Explanation |
|---|---|
| 16 | Incorrect; this is the diploid (2n) number for somatic cells, not linkage groups, which match the haploid set. |
| 8 | Correct; equals n=8, the haploid chromosome count. |
| 4 | Incorrect; no basis in standard diploid genetics—possibly confuses with specific organisms like Drosophila (n=4). |
| Impossible to tell | Incorrect; linkage groups directly equal n in standard cases without polyploidy or aberrations. |
