Sunflowers were domesticated fairly recently from a wild sunflower native to Nor

Question

Sunflowers were domesticated fairly recently from a wild sunflower native to North America and have been under intense artificial selection for increased number of seeds, size of seeds, and sunflower-oil content. Domestic sunflower strains have lower genetic diversity at most loci than do the wild populations. On one chromosome, there is a cluster of loci called LG06 that all show signs of recent positive selection in domestic sunflowers. Some of the commmon alleles at certain of these loci increase seed size and oil content. However, at the other loci in this cluster, the most common allele (in domestic sunflowers) is associated with maladaptive.

Why do domestic sunflowers have lower genetic diversity than wild sunflowers? Why did the LG06 maladaptive alleles become more widespread during the domestication of sunflowers?

Explanation / Answer

Domestic sunflowers perhaps have lower genetic diversity due to a founder effect and probably to strong selection that has eliminated undesirable alleles. It has been seen that sunflowers passed through several genetic bottlenecks during the domestication. There are many reasons that maladaptive traits could have become more common including inbreeding depression, genetic drift, etc. But in this case, they seem to have hitchhiked to fixation in a selective sweep, due to being physically linked to desirable alleles that are responsible to increase seed size and oil content. (The LG in LG06 indicates the linkage group).

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.