Home
Blog
he c1 mutation in maize results in colorless kernels, while plants with at least

he c1 mutation in maize results in colorless kernels, while plants with at least

Daniel Kevins

0 comments

The c1 mutation in maize results in colorless kernels, while plants with at least one copy of the dominant C1 allele produce colored kernels. Also, the wx mutation results in waxy kernels, while plants with at least one coy of the dominant Wx allele produce starchy kernels.

In Cross I, doubly heterozygous F1 plants (C1 c1 Wx wx) were testcrossed to plants pure-breeding for colorless, waxy kernels (c1 c1 wx wx). The test-cross progeny are as follows:

Phenotype	Number
Colored, waxy	310
Colored, starchy	858
Colorless, waxy	781
Colorless, starchy	311
Total : 2260

In Cross II, a different set of doubly heterozygous F1 plants (C1 c1 Wx wx) were testcrossed to plants pure-breeding for colorless, waxy kernels (c1 c1 wx wx). The test-cross progeny are as follows:

Phenotype	Number
Colored, waxy	340
Colored, starchy	115
Colorless, waxy	92
Colorless, starchy	298
Total :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.

Choose 1,2,3,or 4.

1.	The chi-square is 464, P values are above 0.01.This supports linkage of the colorless and waxy genes.
2.	The chi-square is 464, P values are below 0.01.This rejects linkage of the colorless and waxy genes.
3.	The chi-square is 464, P values are above 0.01.This rejects linkage of the colorless and waxy genes.
4.	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.

Choose 1,2,3,or 4.

1.	The chi-square is 225, P values are above 0.01.This rejects linkage of the colorless and waxy genes.
2.	The chi-square is 225, P values are below 0.01.This supports linkage of the colorless and waxy genes.
3.	The chi-square is 225, P values are above 0.01.This supports linkage of the colorless and waxy genes.
4.	The chi-square is 225, P values are below 0.01.This rejects linkage of the colorless and waxy genes

Part C.

Calculate the recombination frequency for cross I.

Enter your answer to three or more decimal places (example 0.127).

Part D

Calculate the recombination frequency for cross II.

Enter your answer to three or more decimal places (example 0.127).

Part E

Are the results of these two experiments mutually compatible with the hypothesis of genetic linkage?

Part E

Are the results of these two experiments mutually compatible with the hypothesis of genetic linkage? Choose 1,2,3,or 4.

1.	No, both sets of data are not compatible with the hypothesis of genetic linkage.
2.	Yes, both sets of data are compatible with the hypothesis of genetic linkage.
3.	Only sets of data for cross IIis compatible with the hypothesis of genetic linkage.
4.	Only sets of data for cross Iis compatible with the hypothesis of genetic linkage.

Part F

What were the genotypes of the two pure-breeding parents that were crossed to produce theF1 plants for Cross I? Choose 1,2,3,or 4.

1.	C1 wx / C1 wx and c1 Wx / c1 Wx.
2.	C1 wx / c1 Wx and C1 wx / c1 Wx.
3.	C1 Wx / c1 wx and C1 Wx / c1 wx.
4.	C1 Wx / C1 Wx and c1 wx / c1 wx.

Part G

What were the genotypes of the two pure-breeding parents that were crossed to produce theF1 plants for Cross II? Choose 1,2,3,or 4.

1.	C1 Wx / C1 Wx and c1 wx / c1 wx.
2.	C1 wx / C1 wx and c1 Wx / c1 Wx.
3.	C1 Wx / c1 wx and C1 Wx / c1 wx.
4.	C1 wx / c1 Wx and C1 wx / c1 Wx.

About the Author

Daniel Kevins

Follow me