Alleles at the P locus control seed color. Plants which are pp have white seeds, white flowers and no pigment in vegetative parts. Plants which are P_ have black seeds, purple flowers and may have varying degrees of pigment on stems and leaves. Seed color can be assessed, visually, based on if the seed is white or not white A gene for mold resistance has been reported and we want to determine its inheritance and whether it is linked to P. For the purposes of this exercise, we will assume that resistance is controlled by a single locus M, and M_ plants are resistant and mm plants are susceptible. Resistance can be measured, under greenhouse conditions, 2 weeks after planting, by injecting each seedling with a spore suspension. After two weeks, the seedlings can be rated as resistant or susceptible, based on whether or not tissue is actively sporulating. For this exercise we will use seed and data from the F10 generation of a recombinant inbred population produced using single seed descent (SSD). SSD means a single seed is selected from each plant at random and planted for the next generation. A homozygous black-seeded, mold-susceptible parent was crossed to a homozygous white seeded and mold resistant parent to create the F1, which was self-pollinated to produce 100 F2 plants. One seed from each of the 100 F2 plants was selected at random and planted to produce 100 F3 plants. In the F3 and in each subsequent generation, a single seed from each plant was taken at random and used to plant the next generation. This process was followed until the F10 generation. Plants at the F10 generation were tested for mold resistance and classified as resistant or susceptible. You have two seed packets – one containing one seed from each of the 52 resistant plants in the F10 and the other containing 1 seed from each of the 48 susceptible plants in the F10. In the packet of seed labelled “resistant”, there are 52 seeds: 45 white and 7 black. In the packet of seed labelled “susceptible” there are 48 seeds: 6 white and 42 black. The goals of the exercise are to determine if the P and M loci are linked and if it is possible to select a black-seeded, mold resistant bean. Test the null hypotheses that each of the two traits (color and disease reaction) is controlled by alleles at a single locus. Show your calculations, calculated chi square, and p value. What do you conclude? Test the null hypothesis that the two traits (color and disease reaction) show independent assortment. Show your calculations, calculated chi square, and p value. What do you conclude? Calculate the percentage of recombination. Convert you observed percentage of recombination to Kosambi centiMorgans. Formula: 0.25*LN((1+2*r)/(1-2*r))*100, where r = recombination. Is the P locus linked to the M locus? If P and M are linked, are they in complete or partial linkage? Based on your answer, is it possible to identify black beans with mold resistance?
Alleles at the P locus control seed color. Plants which are pp have white seeds, white flowers and no pigment in vegetative parts. Plants which are P_ have black seeds, purple flowers and may have varying degrees of pigment on stems and leaves. Seed color can be assessed, visually, based on if the seed is white or not white
A gene for mold resistance has been reported and we want to determine its inheritance and whether it is linked to P. For the purposes of this exercise, we will assume that resistance is controlled by a single locus M, and M_ plants are resistant and mm plants are susceptible. Resistance can be measured, under greenhouse conditions, 2 weeks after planting, by injecting each seedling with a spore suspension. After two weeks, the seedlings can be rated as resistant or susceptible, based on whether or not tissue is actively sporulating.
For this exercise we will use seed and data from the F10 generation of a recombinant inbred population produced using single seed descent (SSD). SSD means a single seed is selected from each plant at random and planted for the next generation. A homozygous black-seeded, mold-susceptible parent was crossed to a homozygous white seeded and mold resistant parent to create the F1, which was self-pollinated to produce 100 F2 plants. One seed from each of the 100 F2 plants was selected at random and planted to produce 100 F3 plants. In the F3 and in each subsequent generation, a single seed from each plant was taken at random and used to plant the next generation. This process was followed until the F10 generation. Plants at the F10 generation were tested for mold resistance and classified as resistant or susceptible.
You have two seed packets – one containing one seed from each of the 52 resistant plants in the F10 and the other containing 1 seed from each of the 48 susceptible plants in the F10. In the packet of seed labelled “resistant”, there are 52 seeds: 45 white and 7 black. In the packet of seed labelled “susceptible” there are 48 seeds: 6 white and 42 black.
The goals of the exercise are to determine if the P and M loci are linked and if it is possible to select a black-seeded, mold resistant bean.
- Test the null hypotheses that each of the two traits (color and disease reaction) is controlled by alleles at a single locus. Show your calculations, calculated chi square, and p value. What do you conclude?
- Test the null hypothesis that the two traits (color and disease reaction) show independent assortment. Show your calculations, calculated chi square, and p value. What do you conclude?
- Calculate the percentage of recombination.
- Convert you observed percentage of recombination to Kosambi centiMorgans. Formula: 0.25*LN((1+2*r)/(1-2*r))*100, where r = recombination.
- Is the P locus linked to the M locus?
- If P and M are linked, are they in complete or partial linkage? Based on your answer, is it possible to identify black beans with mold resistance?
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