(d) Screen and Ordering for Cilia Length Regulators

Q1: What is a forward genetic screen?

A1: It is a "phenotype-to-genotype" strategy.

Q2: How is a forward genetic screen typically carried out?

A2: A population is randomly mutagenised (typically with EMS) to introduce DNA lesions.

Q3: What do researchers look for in the F2 generation during a forward genetic screen for cilia length regulators?

A3: They screen for a specific defect—in this case, abnormal cilia length.

Q4: After identifying a mutant with abnormal cilia length, what is the next step?

A4: Researchers subsequently clone the responsible gene

Q1: What is the first experimental step to order genes that regulate cilia length?

A1: Double mutant construction: cross the "abnormally long" mutant with the "abnormally short" mutant to generate a homozygous double mutant. (Huang and Sternberg)

Q2: After constructing the double mutant, what is the second step?

A2: Phenotypic scoring: observe whether the double mutant cilia are abnormally long or abnormally short. (Wang and Sherwood)

Q3: Which researchers are credited for the double mutant construction method in this context?

A3: Huang and Sternberg.

Q4: Which researchers are credited for the phenotypic scoring approach?

A4: Wang and Sherwoo