Homework SourseIn rice locus A and B are genetically linked 20 map units ap
In rice, locus A and B are genetically linked 20 map units apart. Locus A has two alleles (A>a), while locus B also has two alleles (B>b). A plant heterozygous at both loci in cis configuration is produced.
a) What fraction of the gametes produced by this heterozygous plant will be AB?
b) If this plant undergoes self-fertilization whst fraction of its progeny will be: i) AB/ab? ii) AaBb?
Solution
Answer:
Map unit Distance = % of Recombination frequency
20 mu = 20% recombinants
a) AB gametes = 40%
Explanation:
AB/ab
AB(40%) & ab (40%) gametes are parental combinations= 80%
Ab (10%) & aB(10%) gametes are recombinants = 20%
b).
AB/ab x AB/ab----------------Parents
AB/ab=2/16* (0.4 * 0.4) = 2/16 * 0.16 =0.02 or 1/50
Ab/aB = 2/16 * (0.1 * 0.1) = 2/16 * 0.01 = 0.00125
| AB | Ab | aB | ab | |
| AB | AB/AB | AB/Ab | AB/aB | AB/ab |
| Ab | Ab/AB | Ab/Ab | Ab/aB | Ab/ab |
| aB | aB/AB | aB/Ab | aB/aB | aB/ab |
| ab | ab/AB | ab/Ab | ab/aB | ab/ab |
