Q1 A researcher aims to understand the genetic basis of 1 2

Q1. A researcher aims to understand the genetic basis of 1 2 3 4 5 6 7 8 9 10 locomotion in the diploid nematode Caenorhabditis elegans. Ten different recessive mutations have been obtained, all of which make the worm twitch\" ineffectualy instead of moving with the normal gliding motion. Every homozygous mutant was crossed to every other homozygous mutant, and the locomotion phenotype of the progeny is presented in the table 3 5 6 a) How many genes affecting muscle movement have been 7 identified? Define gene and allele symbols to show which8 mutations are in which genes. Include wildtype alleles. 9 b) Use your gene and allele symbols to show genotype of 10 relevant genes for parents and offspring for the following crosses: + wildtype phenotype observed t - twitching phenotype observed i. homozygous mutant 2 crossed to homozygous mutant 5 ii. homozygous mutant 2 crossed to homozygous mutant 3

Solution

When two mutants are crossed and the resultant F1 progeny shows WT phenotype, it means that both the mutations are located in different genes. i.e. they are non-allelic.

When two mutants are crossed and the resultant F1 progeny shows mutant phenotype, it means that both the mutations are located in the same gene. i.e. they are allelic to each other.

\'+\' means WT phenotype

\'t\' means mutant phenotype

T = WT allele

t = Mutant allele

a. Complementation groups:

i. 1

ii. 2 = 5 = 7 = 9

iii. 3

iv. 6 = 10

v. 8

vi. 10

b. Since 2 and 5 are allelic to each other, all the F1 progeny would show mutant phenotype.

Since 2 and 3 are not allelic to each other, all the F1 progeny would show WT phenotype.