Question

Drosophila and Maize Experiments in Genetics: Monohybrid and Dihybrid Crosses 17 TABLE 1.6 Summary of Data and Calculations for Dihybrid F2 in Maize Calculate the number of kernels expected in each phenotypic category and the deviation between observed and expected (O - E). Observed Expected Deviation Phenotype Number (0) Number (E) (0 - E) Purple Slachy Purple Sweet Yellow Stachy yellow sweet 104 23 32 11 Totals 172

Answer 1

Answer-

When a cross involves 2 pairs of contrasting factors (here color and taste), it is dihybrid cross. In Mendelian dihybrid cross offsprings of F2 generation are expected to be produced in 9:3:3:1 phenotypic ratio.

Explanation for the answer is provided below:

ratio in In endelian Dihybrid cross the phenotypic fa generation will be 9:3:3:1 Sene Genotype Phenotype » ( ap Purple P'p' Yellow 27 (as s Starchy sweet S. PPSS X Pp's's Parental ps 's) - gametes Fi. Ppss – purple, starchy Ppss X PÉSS I Pos- Pweple, starchy P_ss Purple, sweet Pes_ Yellow, starchy p'p's's Yellore, sweet Observed (o) Phenotype Expected (E) (0-) Perlen -96.75404-96-75) = 7.25 3 x172 = 32.25 (25-32.25) = -7-25 Purple, starchy 104 Purple, sweet 25 Yellow, starchy 32 3 x172=32-25 32-32-25) = -0.25 Yellow, sweet 11 11 / 8x 172 = 10.75 (11-10.75 = 0.25 Total 172 172