6. Margaret is studying a population of sunflowers that are genetically variable

Question

6. Margaret is studying a population of sunflowers that are genetically variable in a controlled lab setting. She measures the mean and variance of seed set on 1000 individuals. The phenotypic variance in seed number is 30. She picks one plant to self-pollinate and produces 200 genetically identical progeny. The phenotypic variance in seed number in these progeny is 20. Use this information to answer the questions below. A. Calculate the broad-sense Heritability (H2) pop 1000: Vps 30-Vg+Ve Vg-30-20 pop 200: Vp-20-Vg-Ve Ve-20 H2-Vg/Vp-Vg/(Vg+Ve): 10/(10+20)-10/30= .33 B. What does the broad-sense heritability value tell you about the role of genetics and environment on phenotypic variance in seed number? Parents do not necessarily determine the offspring. C. What does this tell you about the potential ability of seed number change over time due to natural selection? Provide at least two supporting details that supports your interpretation. D. Margret has decided to leave academia and become a lawyer. She has also decided to bring her sunflowers with her and plant them in her garden. She repeats the experiment described above in her yard, and calculates an H2 for seed set to be 0.90. Provide two reason why it is not surprising that this value is different from the one in part A 7. List four ways (of the many possible) the environment causes changes in gene expression (which ultimately determines phenotype). Hint: list ways to regulate gene expression.

Explanation / Answer

C. Potential ability of seed number change over time due to natural selection as the best seed are selected at each consecutive generations. Two supporting details that support our interpretations are:

(i) Bigger seeds are selected at each generation because they are provisioned with maternal resources to survive better then smaller seeds.

(ii) Second factor that tell about the ability of seed number change over time is plant density.

D. It is not surprising that this value is different from part A because

(i) Due to environmental factor.

(ii) Genetic variation

7. Four ways that environment causes change in gene expression are:

(i) Transcription

(ii) Translation

(iii) Post-translational modification

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