Q40 - Drosophila Saturation Mutagenesis
Christiane Nusslein-Volhard and Eric F. Wieschaus carried out an extensive mutation screen to identify all genes involved in segmentation of Drosophila.
In their experiment, adults were exposed to a mutagen, then crosses were carried out. The progeny were analysed for changes in segmentation patterns (such as missing segments).
The graph shows results of analyzing mutations on chromosome 2.
True or false?
Q40.1. The number of segmentation genes identified on chromosome 2 is between 60 and 70.
Q40.2. Analysing 10000 progeny would have led to the identification of substantially more segmentation genes.
Q40.3. Analysis of more than 2000 progeny tended to lead to the identification of new alleles of genes which had already been identified, rather than more new genes.
Q40.4. The frequency of obtaining recessive mutants is higher than dominant mutants as a greater number of progeny are analyzed.
Question reproduced from IBO 2023, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF