Mendel studied a tall variety of pea plants with stemsthat are 20 cm long and a dwarf variety with stems thatare only 12 cm long.a. Under blending theory, how long would you expectthe stems of first and second hybrids to be?b. Under Mendelian rules and assuming stem lengthis controlled by a single gene, what would you expectto observe in the second-generation hybrids if all thefirst-generation hybrids were tall?

Mendel studied a tall variety of pea plants with stemsthat are 20 cm long and a dwarf variety with stems thatare only 12 cm long.a. Under blending theory, how long would you expectthe stems of first and second hybrids to be?b. Under Mendelian rules and assuming stem lengthis controlled by a single gene, what would you expectto observe in the second-generation hybrids if all thefirst-generation hybrids were tall?

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter5: The Inheritance Of Complex Traits

Section: Chapter Questions

Problem 2QP: The text outlines some of the problems Frederick William I encountered in his attempt to breed tall...

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In one study, Gregor Mendel crossed yellow-seeded, tall garden pea with a green-seeded,short garden pea. The F1 offspring were all yellow-seeded and tall. Assumingindependent assortment of these two genes, what phenotypes and proportions did he finamong F2 offspring when the F1 garden peas are allowed to fertilize themselves? Show the solution with punnett square.
Wooly hair is a rare dominant trait found in people of Scandinavian descent in which the hair resembles the wool of a sheep. Amale with wooly hair, who has a mother with straight hair, movesto an island that is inhabited by people who are not of Scandinavian descent. Assuming that no other Scandinavians immigrate tothe island, what is the probability that a great-grandchild of thismale will have wooly hair? (Hint: You may want to draw a pedigree to help you figure this out.) If this wooly-haired male haseight great-grandchildren, what is the probability that one out ofeight will have wooly hair?
The accompanying pedigree shows a very unusual inheritance pattern that actually did exist. All progeny areshown, but the fathers in each mating have been omittedto draw attention to the remarkable pattern.a. Concisely state exactly what is unusual about thispedigree.b. Can the pattern be explained by Mendelianinheritance?
Mendel obtained his initial pea plant varieties from local breeders who were developing new varieties that might be useful or interesting. To generate these new varieties, breeders formed hybrids between existing varieties of different phenotypic characteristics by cross-pollination, using techniques they doubtless taught to Mendel. After producing a hybrid, they allowed several generations of self-pollination, as happens naturally if the flowers are not disturbed. i. How many generations would it take for a breeder to have produced new pure-breeding varieties using this approach? ii. What is the probability that an individual in each of these generations (F2, F3, and F10) would be homozygous for one or the other allele of this gene? [Broad hint: if they’re not heterozygous, they’re homozygous!] please answer and explain properly
. Considering the yellow and green pea color phenotypes studied by Gregor Mendel:a. What is the biochemical function of the proteinthat is specified by the gene responsible for thepea color phenotype?b. A null allele of a gene is an allele that does notspecify any of the biochemical function that thegene normally provides. Of the two alleles Y and y,which is more likely to be a null allele?c. In terms of the underlying biochemistry, why is theY allele dominant to the y allele?d. Why are peas that are yy homozygotes green?e. The amount of the protein specified by a gene isroughly proportional to the number of functionalcopies of the gene carried by a cell or individual.What do the phenotypes of YY homozygotes, Yyheterozygotes, and yy homozygotes tell us aboutthe amount of the Sgr enzyme (the product of thepea color gene) needed to produce a yellow color?
If the white-flowered parental variety in Figure 1-3 werecrossed to the first-generation hybrid plant in that figure,what types of progeny would you expect to see and inwhat proportions?
Galactosemia is a recessive human disease that istreatable by restricting lactose and glucose in the diet.Susan Smithers and her husband are both heterozygous for the galactosemia gene.a. Susan is pregnant with twins. If she hasfraternal (nonidentical) twins, what is theprobability both of the twins will be girls whohave galactosemia?b. If the twins are identical, what is the probabilitythat both will be girls and have galactosemia?For parts (c–g), assume that none of the children isa twin.c. If Susan and her husband have four children, whatis the probability that none of the four will havegalactosemia?d. If the couple has four children, what is the probability that at least one child will have galactosemia?e. If the couple has four children, what is the probability that the first two will have galactosemia andthe second two will not?f. If the couple has three children, what is the probability that two of the children will have galactosemia and one will not, regardless of order?g. If…
You self-fertilize an F1 plant to produce the F2 generation. Based on Mendelian principles of inheritance, what fraction of the F2 generation do you expect to be short with round, green seeds? HINT: Solving this problem will require a very large Punnett square (8 x 8), but you can easily solve it using the Multiplication Rule
For all seven characters described in the data of Mendel allowed the F2 plants to self-fertilize. He found that whenF2 plants with recessive traits were crossed to each other, theyalways bred true. However, when F2 plants with dominant traitswere crossed, some bred true but others did not. A summary ofMendel’s results is shown to the right When considering the data in this table, keep in mind that theydescribe the characteristics of the F2 generation parents that haddisplayed a dominant phenotype. These data were deduced byanalyzing the outcome of the F3 generation. Based on Mendel’slaws, explain why the ratios were approximately 1:2
In classical Mendelian genetics, how can one check the genotype of a parent (A) expressing the characters of a dominant allele? Select one: a. By performing a back cross with a recessive homozygote parent (B). If the A parent is homozygote for the dominant allele, then all the individuals from the F1 will display the dominant character. If the parent A was, instead, a heterozygote, then 50% of the F1 progeny will express the recessive character (homozygote recessive) and 50% the dominant one (heterozygotes). b. It is impossible to check such genotype without using specific molecular assays. c. By performing a back cross with a dominant homozygote parent (B). If the A parent is homozygote for the dominant allele, then all the individuals from the F1 will display the dominant character.
A rare recessive allele inherited in a Mendelian mannercauses the disease cystic fibrosis. A phenotypically normal man whose father had cystic fibrosis marries a phenotypically normal woman from outside the family, andthe couple consider having a child.a. Draw the pedigree as far as described.b. If the frequency in the population of heterozygotesfor cystic fibrosis is 1 in 50, what is the chance that thecouple’s first child will have cystic fibrosis?c. If the first child does have cystic fibrosis, what is theprobability that the second child will be normal?
. Which part of the pedigree in Figure 2-23 in your opinion best demonstrates Mendel’s first law?