Ch. 3 - Mendelian Genetics

Klug - Essentials of Genetics 10th Edition

Klug10th EditionEssentials of GeneticsISBN: 9780135588789Not the one you use?Change textbook

Klug 10th Edition

Ch. 3 - Mendelian Genetics

Problem 18

Chapter 3, Problem 18

Consider three independently assorting gene pairs, A/a, B/b, and C/c, where each demonstrates typical dominance (A-, B-, C-) and recessiveness (aa, bb, cc). What is the probability of obtaining an offspring that is AABbCc from parents that are AaBbCC and AABbCc?

Verified step by step guidance

Identify the genotypes of the parents: Parent 1 is AaBbCC and Parent 2 is AABbCc.

Determine the possible gametes each parent can produce for each gene pair by considering their alleles and independent assortment.

Calculate the probability of the offspring inheriting the genotype AABbCc by multiplying the probabilities for each gene pair separately:

For gene A: Calculate the probability of inheriting 'AA' from the parents.

For gene B: Calculate the probability of inheriting 'Bb' from the parents.

For gene C: Calculate the probability of inheriting 'Cc' from the parents.

Multiply the probabilities from each gene pair together to get the overall probability of the offspring being AABbCc.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mendelian Inheritance and Independent Assortment

Mendelian inheritance describes how alleles segregate and assort independently during gamete formation. Independent assortment means that gene pairs located on different chromosomes are inherited separately, allowing the calculation of combined probabilities by multiplying individual gene probabilities.

Genotype Probability Calculation

Calculating the probability of a specific genotype involves determining the chance of inheriting each allele from the parents. For each gene, the probability depends on the parents' genotypes and the possible gametes they can produce, which are combined to find the overall likelihood of the offspring's genotype.

Dominance and Genotype Notation

Dominance refers to the relationship between alleles where the dominant allele masks the recessive one in phenotype. Genotype notation uses uppercase letters for dominant alleles and lowercase for recessive, with heterozygous (e.g., Aa) and homozygous (e.g., AA or aa) forms indicating allele combinations.

Recommended video:

Guided course

04:37

Variations on Dominance

Related Practice

Textbook Question

The following are F₂ results of two of Mendel's monohybrid crosses.

For each cross, state a null hypothesis to be tested using x² analysis. Calculate the x² value and determine the p value for both. Interpret the p-values. Can the deviation in each case be attributed to chance or not? Which of the two crosses shows a greater amount of deviation?

649

views

Textbook Question

In assessing data that fell into two phenotypic classes, a geneticist observed values of 250:150. She decided to perform a $χ$ ² analysis by using the following two different null hypotheses:

(a) the data fit a 3:1 ratio, and

(b) the data fit a 1:1 ratio.

Calculate the $χ$ ² values for each hypothesis. What can be concluded about each hypothesis?

855

views

Textbook Question

The basis for rejecting any null hypothesis is arbitrary. The researcher can set more or less stringent standards by deciding to raise or lower the p value used to reject or not reject the hypothesis. In the case of the chi-square analysis of genetic crosses, would the use of a standard of p = 0.10 be more or less stringent about not rejecting the null hypothesis? Explain.

813

views

Textbook Question

Consider the following pedigree.

Predict the mode of inheritance of the trait of interest and the most probable genotype of each individual. Assume that the alleles A and a control the expression.

4334

views

rank