Ch. 2 - Transmission Genetics

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook

Sanders 3rd Edition

Ch. 2 - Transmission Genetics

Problem 41d

Chapter 2, Problem 41d

Humans vary in many ways from one another. Among many minor phenotypic differences are the following five independently assorting traits that (sort of) have a dominant and a recessive phenotype: (1) forearm hair (alleles F and f )—the presence of hair on the forearm is dominant to the absence of hair on the forearm; (2) earlobe form (alleles E and e)—unattached earlobes are dominant to attached earlobes; (3) widow's peak (alleles W and w)—a distinct 'V' shape to the hairline at the top of the forehead is dominant to a straight hairline; (4) hitchhiker's thumb (alleles H and h)—the ability to bend the thumb back beyond vertical is dominant and the inability to do so is recessive; and (5) freckling (alleles D and d)—the appearance of freckles is dominant to the absence of freckles. In reality, the genetics of these traits are more complicated than single gene variation, but assume for the purposes of this problem that the patterns in families match those of other single-gene variants.
If a couple with the genotypes Ff Ee Ww Hh Dd and Ff Ee Ww Hh Dd have children, what is the chance the children will inherit the following characteristics?

the genotype Ff EE Ww hh dd

Verified step by step guidance

Step 1: Understand the problem. The question asks for the probability of a child inheriting a specific genotype (Ff EE Ww hh dd) from parents who both have the genotype Ff Ee Ww Hh Dd. Each trait is independently assorting, meaning we can calculate the probability for each gene separately and then multiply the probabilities together.

Step 2: Analyze the inheritance of the first gene (Ff). Both parents are heterozygous (Ff), so the offspring can inherit either F or f from each parent. Use a Punnett square to determine the probabilities for the offspring's genotype. The probability of inheriting Ff is 50%.

Step 3: Analyze the inheritance of the second gene (EE). Both parents are heterozygous (Ee), so the offspring can inherit either E or e from each parent. Use a Punnett square to determine the probabilities for the offspring's genotype. The probability of inheriting EE is 25%.

Step 4: Analyze the inheritance of the third gene (Ww). Both parents are heterozygous (Ww), so the offspring can inherit either W or w from each parent. Use a Punnett square to determine the probabilities for the offspring's genotype. The probability of inheriting Ww is 50%.

Step 5: Analyze the inheritance of the fourth and fifth genes (hh and dd). For hh, both parents are heterozygous (Hh), so the probability of inheriting hh is 25%. For dd, both parents are heterozygous (Dd), so the probability of inheriting dd is also 25%. Multiply the probabilities for all five traits together to find the overall probability of the child having the genotype Ff EE Ww hh dd.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

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

Mendelian Genetics

Mendelian genetics is the study of how traits are inherited through generations based on the principles established by Gregor Mendel. It involves understanding dominant and recessive alleles, where dominant alleles mask the expression of recessive ones. This framework helps predict the probability of offspring inheriting specific traits based on parental genotypes.

Punnett Square

A Punnett square is a diagram used to predict the genetic makeup of offspring from two parents. By organizing the possible gametes from each parent, it allows for the visualization of potential genotype combinations. This tool is essential for calculating the probabilities of specific traits appearing in the offspring, such as the genotype Ff EE Ww hh dd in this scenario.

Independent Assortment

Independent assortment is a principle stating that alleles for different traits segregate independently of one another during gamete formation. This means that the inheritance of one trait does not influence the inheritance of another, allowing for a variety of combinations in offspring. Understanding this concept is crucial for analyzing the inheritance patterns of multiple traits simultaneously, as seen in the question.

Recommended video:

Guided course

04:58

Gamete Genetics and Independent Assortment

Related Practice

Textbook Question

A pure-breeding fruit fly with the recessive mutation cut wing, caused by the homozygous cc genotype, is crossed to a pure-breeding fly with normal wings, genotype CC. Their F₁ progeny all have normal wings. F₁ flies are crossed, and the F₂ progeny have a 3:1 ratio of normal wing to cut wing. One male F₂fly with normal wings is selected at random and mated to an F₂ female with normal wings. Using all possible genotypes of the F₂ flies selected for this cross, list all possible crosses between the two flies involved in this mating, and determine the probability of each possible outcome.

671

views

Textbook Question

Humans vary in many ways from one another. Among many minor phenotypic differences are the following five independently assorting traits that (sort of) have a dominant and a recessive phenotype: (1) forearm hair (alleles F and f )—the presence of hair on the forearm is dominant to the absence of hair on the forearm; (2) earlobe form (alleles E and e)—unattached earlobes are dominant to attached earlobes; (3) widow's peak (alleles W and w)—a distinct 'V' shape to the hairline at the top of the forehead is dominant to a straight hairline; (4) hitchhiker's thumb (alleles H and h)—the ability to bend the thumb back beyond vertical is dominant and the inability to do so is recessive; and (5) freckling (alleles D and d)—the appearance of freckles is dominant to the absence of freckles. In reality, the genetics of these traits are more complicated than single gene variation, but assume for the purposes of this problem that the patterns in families match those of other single-gene variants.

If a couple with the genotypes Ff Ee Ww Hh Dd and Ff Ee Ww Hh Dd have children, what is the chance the children will inherit the following characteristics?

the same phenotype as the parents

408

views

Textbook Question

If a couple with the genotypes Ff Ee Ww Hh Dd and Ff Ee Ww Hh Dd have children, what is the chance the children will inherit the following characteristics?

four dominant traits and one recessive trait

410

views

Textbook Question

Situs inversus is a congenital condition in which the major visceral organs are reversed from their normal positions. Investigations into the genetics of this abnormality revealed that individuals with at least one dominant allele (SI) of an autosomal gene are normal but, surprisingly, of individuals that are homozygous for a recessive allele (si), 1/2 are situs inversus and 1/2 are normal.

What genotypes and phenotypes are expected in progeny from a cross of two si si individuals?

415

views

Textbook Question

In chickens, the presence of feathers on the legs is due to a dominant allele (F), and the absence of leg feathers is due to a recessive allele (f). The comb on the top of the head can be either pea-shaped, a phenotype that is controlled by a dominant allele (P), or a single comb controlled by a recessive allele (p). The two genes assort independently. Assume that a pure-breeding rooster that has feathered legs and a single comb is crossed with a pure-breeding hen that has no leg feathers and a pea-shaped comb. The F₁ are crossed to produce the F₂. Among the resulting F₂, however, only birds with a single comb and feathered legs are allowed to mate. These chickens mate at random to produce F₃ progeny. What are the expected genotypic and phenotypic ratios among the resulting F₃ progeny?

If a couple with the genotypes Ff Ee Ww Hh Dd and Ff Ee Ww Hh Dd have children, what is the chance the children will inherit the following characteristics?

all recessive traits

505

views