Over time, many dihybrid cross experiments of autosomally-linked genes in sweet pea plants (Lathyrus odoratus) have been carried out by reputed scientists. Which of the following best explains the presence of some non-parental phenotypes in the offspring of such crosses?
Correct answer: A. Crossing over has occurred, leading to the production of recombinant plants
- A. Crossing over has occurred, leading to the production of recombinant plants
- B. The scientists made errors such as not cleaning the small paint brush that they used to transfer pollen grains between plants
- C. Independent assortment had occurred, so unusual phenotypes are to be expected
- D. Only plants of one gender exhibit parental phenotypes due to linkage
Explanation
Linked genes are normally inherited together, but crossing over between them during meiosis produces recombinant gametes and so some offspring with non parental phenotypes. Independent assortment does not apply to linked genes, and errors in technique or the sex of the plant do not explain the consistent appearance of recombinants.
This question appeared on the UHS MDCAT 2026 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Gene Linkage and Crossing Over
Linked genes lie on the same chromosome and tend to pass together, unlike genes that assort independently on different chromosomes. The topic connects linkage with homologous pairing, crossing over during prophase I of meiosis, recombinant and parental offspring, and recombination frequency as an estimate of gene distance.
Practise Inheritance
1,245 free Inheritance MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Biology questions like this
Biology is on 8 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.