If two heterozygous animals for two independently assorting loci are crossed, the expected phenotypic ratio under complete dominance is:
Correct answer: A. 9:3:3:1
- A. 9:3:3:1
- B. 1:1:1:1
- C. 3:1
- D. 1:2:1
Explanation
A dihybrid cross between two heterozygotes gives the classic 9:3:3:1 phenotypic ratio when the loci assort independently and each locus shows complete dominance. A 3:1 ratio applies to a single-locus monohybrid cross.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Animal Breeding and Genetics
Covers genes, chromosomes, inheritance, genetic variation, mutations, heritability and quantitative traits in livestock. It also includes selection methods, breeding systems, inbreeding, crossbreeding, heterosis and evaluation of traits such as growth, milk yield, fertility and disease resistance.
Practise Animal Breeding and Genetics
60 free Animal Breeding and Genetics MCQs from Veterinary Science, 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 Veterinary Science questions like this
Veterinary Science is on this paper prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for it.
More Animal Breeding and Genetics questions
The accuracy of an estimated breeding value is the correlation between the estimated breeding value and the:
A threshold trait in livestock is one that is:
Positive assortative mating occurs when animals are mated to partners that are:
A genetic correlation of -0.80 between two traits indicates that selection for higher values of one trait will generally:
In dairy cattle, a sire's predicted transmitting ability for milk yield is approximately what fraction of his estimated breeding value?
A backcross in animal breeding is produced when an offspring is mated with its: