In Cross 1, pure-breeding colored, starchy kernel plants (C1Wx/C1Wx) were crossed to plants pure-breeding for colorless, waxy kernels (c1 wx/c1 wx). The F1 of this cross were test-crossed to colorless, waxy plants. The test-cross progeny are as follows:
| Phenotype |
Number |
| Colored, waxy |
310 |
| Colored, starchy |
858 |
| Colorless, waxy |
781 |
| Colorless, starchy |
311 |
| |
2260 |
In Cross 2, plants pure-breeding for colored, waxy kernels ( C1 wx/C1 wx) and colorless, starchy kernels (c1 Wx/c1 Wx) were mated, and their F1 were test-crossed to colorless, waxy plants. The test-cross progeny are as follows:
| Phenotype |
Number |
| Colored, waxy |
340 |
| Colored, starchy |
115 |
| Colorless, waxy |
92 |
| Colorless, starchy |
298 |
| |
845
|
In experiments published in 1918 that sought to verify and expand the genetic linkage and recombination theory proposed by Morgan, Thomas Bregger studied potential genetic linkage in corn ( Zea mays) for genes controlling kernel color (colored is dominant to colorless) and starch content (starchy is dominant to waxy). Bregger performed two crosses.
Part A
For cross I, determine whether genetic linkage or independent assortment is more strongly supported by the data.
A)The chi-square is 464, P values are above 0.01.This supports linkage of the colorless and waxy genes.
B)The chi-square is 464, P values are below 0.01.This rejects linkage of the colorless and waxy genes.
C)The chi-square is 464, P values are above 0.01.This rejects linkage of the colorless and waxy genes.
D)The chi-square is 464, P values are below 0.01.This supports linkage of the colorless and waxy genes.
Part B
For cross II, determine whether genetic linkage or independent assortment is more strongly supported by the data.
A)The chi-square is 225, P values are below 0.01.This rejects linkage of the colorless and waxy genes
B)The chi-square is 225, P values are below 0.01.This supports linkage of the colorless and waxy genes.
C)The chi-square is 225, P values are above 0.01.This supports linkage of the colorless and waxy genes.
D)The chi-square is 225, P values are above 0.01.This rejects linkage of the colorless and waxy genes.
Part C
Calculate the recombination frequency for cross I.
Enter your answer to two decimal places (example 0.12).
Part D
Calculate the recombination frequency for cross II.
Enter your answer to two decimal places (example 0.12).
Part E
Are the results of these two experiments mutually compatible with the hypothesis of genetic linkage?
A)Only sets of data for cross IIis compatible with the hypothesis of genetic linkage.
B)Yes, both sets of data are compatible with the hypothesis of genetic linkage.
C)No, both sets of data are not compatible with the hypothesis of genetic linkage.
D)Only sets of data for cross Iis compatible with the hypothesis of genetic linkage.