In: Biology
10] You are studying the inheritance of three genes in the
scorpion fly Panorpa communis. You have identified three
different autosomal recessive traits, lavender eyes, green body and
pointed wings. These phenotypes are caused by
alleles in thee different genes, x, y, and z respectively. Wild
type flies have red eyes, brown body, and straight wings (x+,
y+ and z+). You cross two different pure breeding and obtain a
wild-type F1. You then cross the F1 to a true-breeding
line that has all three recessive traits and obtain 100 progeny
whose numbers and phenotype are listed below:
Phenotype Number
Wild type 3
Lavender eyes, green body, pointed wings 7
Lavender eyes, pointed wings 34
Green body 36
Green body, pointed wings 8
Lavender eyes 12
A] Using the genetic notation given in the question, write the
proper genotypes of the two parental pure breeding lines?
B] How are the three genes located relative to each other
C] Using the map distances you calculated above in part [B], if F1
flies were intercrossed, what frequency of the resulting
F2 would have lavender eyes, green body and pointed wings?
Answer-
A) Pure breeding parents' genotype i) y+ x z / y+ x z; ii) y x+ z+ / y x+ z+
B) gene sequence - y -10mu- x -20mu- z
C) frequency will be 0.25%
The explanation is given below: