Question

Pick the correct answer choice:

15.

QTL mapping and GWA (association) mapping are two different methods used to identify genes that affect complex traits. Which of the following statements is true about BOTH methods?

This method requires that the experimenter make crosses between different strains to produce a mapping population. This method can scan the entire genome to find QTL for a trait. This method can easily identify the specific genes that represent the QTL. This method may sample a large number of individuals from a population that is variable for the trait being studied. This method is typically a test of two alleles that differ between the two parents of the mapping population.

(Problem 35a) You are studying proteins having roles in translation in the mouse. By BLAST analysis of the predicted proteins of the mouse genome, you identify a set of mouse genes that encode proteins with sequences similar to those of known eukaryotic translation-initiation factors. You are interested in determining the phenotypes associated with loss-of-function mutations of these genes. Would you use forward- or reverse-genetics approaches to identify these mutations?

forward reverse

Answer 1

15. This method can scan the entire genome to find QTL for a trait.

35a. "Reverse" is the correct option.

Because we have known proteins and want to determine the phenotypes associated with loss-of-function mutations in the genes that encoded them.

Forward genetics is used to identify the heritable differences based on their phenotypes and map locations. It precedes the molecular analysis of the gene products. On the other hand, reverse genetics starts with a known protein/mRNA and focuses on mutating the gene that encodes it to discover the phenotype associated with the gene/protein.