Question

What is a major advantage of using a modifier screen as opposed to a primary screen? Multiple Choice O Modifier screens are easier to perform o Modifier screens are performed with chemically mutagenized flies so all genes that affect development should be identified more rapidly than screening for spontaneous mutants O Modifier screens can be used to identify pleiotropic genes. Modifier screens use a random selection of flies based on their morphology and therefore should identify all genes involved in development

Answer 1

1. A major advantage of using a modifier screen as opposed to a primary screen is that:Modifier screen are performed with chemically mutagenized flies so all genes that affect development should be identified more rapidly than screening for spontaneous mutants.

A modifier screen is a screen that involves looking at F1s after mutagenesis,so that to find dominant suppressors and dominant enhancers.

2. Mosaic analysis allows the homozygous loss-of-function which is to be assayed in a heterozygous animal.

In which cells is wingless required for normal wing development in Drosophila can be answered by mosaic analysis.