Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 4: Problem 5

In foxes, two alleles of a single gene, \(P\) and \(p,\) may result in lethality \((P P),\) platinum coat \((P p),\) or silver coat \((p p) .\) What ratio is obtained when platinum foxes are interbred? Is the \(P\) allele behaving dominantly or recessively in causing (a) lethality; platinum coat color?

Short Answer

Expert verified
Answer: The ratio obtained when platinum foxes are interbred is 1:2:1 for lethality:platinum:silver. The P allele behaves recessively in causing lethality and dominantly in causing platinum coat color.

Step by step solution

01

Set up the Punnett square

To set up the Punnett square, we list the possible gametes from the two platinum foxes (\(Pp\)) along the top and side margins of the square. In this case, each platinum fox can produce two types of gametes: \(P\) and \(p\).
02

Fill the Punnett square with the offsprings' genotypes

Now, we can fill the square with the offspring genotypes by combining gametes. The Punnett square for this cross would look like: | | P | p | |---|---|---| | P | PP | Pp| | p | Pp | pp|
03

Find the resulting ratio

Identify the offspring genotypes from the Punnett square and count the instances of each genotype to find the resulting ratio. We have: 1 \(PP\) (lethality) 2 \(Pp\) (platinum coat) 1 \(pp\) (silver coat) Therefore, the ratio obtained when platinum foxes are interbred is 1:2:1 for lethality:platinum:silver.
04

Determine whether the P allele behaves dominantly or recessively in causing lethality and platinum coat color

(a) Lethality: The \(P\) allele causes lethality only in the homozygous \(PP\) condition, which means it behaves recessively in causing lethality, as it needs another \(P\) allele to exhibit the lethal trait. (b) Platinum coat color: The platinum coat occurs in the heterozygous \(Pp\) condition. In this case, the \(P\) allele is behaving dominantly, as the presence of one \(P\) allele is enough to produce a platinum coat color, and it masks the effect of the \(p\) allele.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A geneticist from an alien planet that prohibits genetic research brought with him two true-breeding lines of frogs. One frog line croaks by uttering "rib-it rib-it" and has purple eyes. The other frog line croaks by muttering "knee- deep knee-deep" and has green eyes. He mated the two frog lines, producing \(F_{1}\) frogs that were all utterers with blue eyes. A large \(\mathrm{F}_{2}\) generation then yielded the following ratios: \(27 / 64\) blue, utterer \(12 / 64\) green, utterer \(9 / 64\) blue, mutterer \(9 / 64\) purple, utterer \(4 / 64\) green, mutterer \(3 / 64\) purple, mutterer (a) How many total gene pairs are involved in the inheritance of both eye color and croaking? (b) Of these, how many control eye color, and how many control croaking? (c) Assign gene symbols for all phenotypes, and indicate the genotypes of the \(P_{1}, F_{1},\) and \(F_{2}\) frogs. (d) After many years, the frog geneticist isolated true-breeding lines of all six \(\mathrm{F}_{2}\) phenotypes. Indicate the \(\mathrm{F}_{1}\) and \(\mathrm{F}_{2}\) phenotypic ratios of a cross between a blue, mutterer and a purple, utterer.

In this chapter, we focused on many extensions and modifications of Mendellan principles and ratios. In the process, we encountered many opportunities to consider how this information was acquired. Answer the following fundamental questions: (a) How were early geneticists able to ascertain inheritance patterns that did not fit typical Mendelian ratios? (b) How did geneticists determine that inheritance of some phenotypic characteristics involves the interactions of two or more gene pairs? How were they able to determine how many gene pairs were involved? (c) How do we know that specific genes are located on the sexdetermining chromosomes rather than on autosomes? (d) For genes whose expression seems to be tied to the gender of individuals, how do we know whether a gene is X-linked in contrast to exhibiting sex- limited or sex-influenced inheritance? (e) How was extranuclear inheritance discovered?

In humans, the ABO blood type is under the control of autosomal multiple alleles. Red-green color blindness is a recessive X-linked trait. If two parents who are both type A and have normal vision produce a son who is color- blind and type \(0,\) what is the probability that their next child will be a female who has normal vision and is type \(0 ?\)

In cattle, coats may be solid white, solid black, or black-and-white spotted. When true-breeding solid whites are mated with truebreeding solid blacks, the \(\mathrm{F}_{1}\) generation consists of all solid white individuals. After many \(\mathrm{F}_{1} \times \mathrm{F}_{1}\) matings, the following ratio was observed in the \(\mathrm{F}_{2}\) generation: \(12 / 16\) solid white \(3 / 16\) black-and-white spotted \(1 / 16\) solid black Explain the mode of inheritance governing coat color by determining how many gene pairs are involved and which genotypes yield which phenotypes. Is it possible to isolate a true-breeding strain of black-and-white spotted cattle? If so, what genotype would they have? If not, explain why not.

Three gene pairs located on separate autosomes determine flower color and shape as well as plant height. The first pair exhibits incomplete dominance, where color can be red, pink (the heterozygote), or white. The second pair leads to the dominant personate or recessive peloric flower shape, while the third gene pair produces either the dominant tall trait or the recessive dwarf trait. Homozygous plants that are red, personate, and tall are crossed with those that are white, peloric, and dwarf. Determine the \(F_{1}\) genotype(s) and phenotype(s). If the \(F_{1}\) plants are inter. bred, what proportion of the offspring will exhibit the same phenotype as the \(\mathrm{P}_{1}\) plants?
See all solutions

Recommended explanations on Biology Textbooks

Biology Experiments

Read Explanation

Cellular Energetics

Read Explanation

Biological Molecules

Read Explanation

Communicable Diseases

Read Explanation

Energy Transfers

Read Explanation

Cell Cycle

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free