Exam 4 Review & Notes

E a and t are linked m is unlinked 8 in the three

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Unformatted text preview: not need to display the trait for their child to.) 7. Yellow pea color (Y) is dominant to green (y), and smooth pea shape (S) is dominant to wrinkled (s). These genes assort independently. A plant is grown from a yellow, smooth pea. A test cross is performed with this plant, and the resul8ng peas are all yellow, but half are smooth and half are wrinkled. The genotype of the original pea was: a) YS b) YYSS c) YySS d) YySs e) YYSs 7. Yellow pea color (Y) is dominant to green (y), and smooth pea shape (S) is dominant to wrinkled (s). These genes assort independently. A plant is grown from a yellow, smooth pea. A test cross is performed with this plant, and the resul8ng peas are all yellow, but half are smooth and half are wrinkled. The genotype of the original pea was: a) YS b) YYSS c) YySS d) YySs e) YYSs Using the info above we can write what we know about the genotypes: P Y/- ; S/- x y/y ; s/s ê༎ F1 Y/- ; S/- and Y/- ; s/s The fact that all of the offspring are yellow suggests that the unknown parent must be YY, otherwise we would see some green offspring from the testcross. The half wrinkled half smooth offspring tells us that this parent must have also been S/s. Therefore the parents genotype is: YYSs 8. In the three point cross AaMmTt by aammh, the following phenotypes among the progeny were obtained: AMT- 25 amt- 25 AmT- 425 aMt- 425 AMt- 275 amT- 275 Amt- 4,275 aMT- 4,275 The order of these genes is: a) A- M- T b) A- T- M c) M- A- T d) M and T are linked, A is unlinked. e) A and T are linked, M is unlinked. 8. In the three point cross AaMmTt by aammh, the following phenotypes among the progeny were obtained: AMT- 25 amt- 25 –> double recombinants (smallest class) AmT- 425 aMt- 425 AMt- 275 amT- 275 Amt- 4,275 aMT- 4,275 –> non recombinant class (largest class) The order of these genes is: a) A- M- T b) A- T- M c) M- A- T d) M and T are linked, A is unlinked. e) A and T are linked, M is unlinked. To determine the gene that's in the middle, you figure out which gene you have to switch in the double- recombinants to get back to the non- recombinant class. Which is A, therefore the the order must be MAT, given that we kno...
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