Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 21, Problem 2P
When an allele is dominant, why does it not always increase in frequency to produce the
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When an allele is dominant, why does it not alwaysincrease in frequency to produce the phenotypeproportion of 3:1 (3/4 dominant : 1/4 recessiveindividuals) in a population?
This lab exercise requires that we count certain Mendelian traits among students present in the lab. Your professor will explain each trait being addressed and will then ask students to identify if they are dominant or recessive for that specific trait. The collected traits will then be plugged into the Hardy-Weinberg Equilibrium formula in order to calculate frequency of Homozygous dominant, Heterozygous and Homozygous recessive individuals in the same.
p2 + 2pq + q2 = 100
given data:
trait: hair swirl
19 individuals total.
10 had the homozygous dominant hair swirl trait: clockwise
the nine other were recessive
please do a step by step explanation with the calculation using this data, as I am very unfamiliar with what values mean what and the equation itself
thank you!
In a certain population of frogs, 120 are green, 60 are brownish-green, and 20 are brown. The allele for brown is denoted GB, and the allele for green is designated GG. These two alleles are incompletely dominant to each other.
What is the frequency of genotype GGGG in this population?
Chapter 21 Solutions
Genetics: From Genes to Genomes
Ch. 21 - Choose the best matching phrase in the right...Ch. 21 - When an allele is dominant, why does it not always...Ch. 21 - A population with an allele frequency p of 0.5 and...Ch. 21 - In a certain population of frogs, 120 are green,...Ch. 21 - Which of the following populations are at...Ch. 21 - A dominant mutation in Drosophila called Delta...Ch. 21 - A large, random mating population is started with...Ch. 21 - Prob. 8PCh. 21 - Alkaptonuria is a recessive autosomal genetic...Ch. 21 - Two hypothetical lizard populations found on...
Ch. 21 - It is the year 1998, and the men and women sailors...Ch. 21 - a. Alleles of genes on the X chromosome can also...Ch. 21 - In 1927, the ophthalmologist George Waaler tested...Ch. 21 - The equation p2 2pq q2> = 1 representing the...Ch. 21 - A gene has two alleles A frequency = p and a...Ch. 21 - Some people can taste the bitter compound...Ch. 21 - Androgenetic alopecia pattern baldness is a...Ch. 21 - The following figure shows the FBI-style analysis...Ch. 21 - Why is the elimination of a fully recessive...Ch. 21 - Tristan da Cunha is a group of small islands in...Ch. 21 - Small population size causes genetic drift because...Ch. 21 - Three basic predictions underlie genetic drift in...Ch. 21 - A mouse mutation with incomplete dominance t =...Ch. 21 - In Drosophila, the vestigial wings recessive...Ch. 21 - In a population of infinite size, three loci A, B,...Ch. 21 - You have identified an autosomal gene that...Ch. 21 - In Europe, the frequency of the CF allele causing...Ch. 21 - An allele of the G6PD gene acts in a recessive...Ch. 21 - Explain why evolutionary biologists monitor...Ch. 21 - Tiny foxes live on the Channel Islands off the...Ch. 21 - What is the most straightforward evidence at the...Ch. 21 - In March 2013, the American Journal of Human...Ch. 21 - If you go back 40 generations into your biological...Ch. 21 - In Fig. 21.17, to what part of the world does...Ch. 21 - Predict the DNA sequences at the four nodes...Ch. 21 - A cladogram not drawn to scale for the taxonomic...Ch. 21 - As noted in Fig. 21.22, humans now living in...Ch. 21 - As of this writing in 2016, no Neanderthal-derived...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- There are 5 individuals in a population. Blue is dominant to orange and there is 1 homozygous dominant, 1 heterozygote, and 3 homozygous recessive individuals. What is the observed allele frequency of the orange allele?arrow_forwardAn autosomal locus has alleles A and a. We are given the frequency of individuals with the autosomal recessive phenotype. Which of the following statements is TRUE? Choose all that are true. Note: HWE = Hardy-Weinberg equilibrium a) If we assume HWE, we can calculate both allele frequencies b) If we assume HWE, we can calculate the genotype frequencies that we weren't given c) We can calculate both allele frequencies even if we don't assume HWE d) We can calculate q = Freq(a) even if we don't assume HWE e) Even if we don't assume HWE, we can calculate the genotype frequencies that we weren't givenarrow_forwardFur colour in mice is a single gene trait controlled by two alleles. In a population of 100 mice, 30 are homozygous dominant, 50 are heterozygous dominant, and 20 are homozygous recessive. What is the frequency of the dominant allele in the population?arrow_forward
- In corn, kernel color is governed by a dominant allele for white color (W) and by a recessive allele for yellow (w). A random sample of 152 kernels from a population that is in Hardy- Weinberg equilibrium reveals that 35 kernels are yellow and 117 kernels are white. What is the frequency of individuals with the homozygous dominant genotype?arrow_forwardIn Hereford cattle, the phenotypic expression of coat pattern called line-back (a white line down the center of the back, extending almost to the tail) is considered undesirable. The gene which causes line-back is recessive and autosomal. If 7 cows out of 100 cattle express this trait, what is the allele frequency for this trait? If the line-back cows are not included in the mating population (W22=0), how many line-back cows will be found in the next generation? (Assume 100 cows in the next generation.) can u ansewer the second questionarrow_forwardIf 120 of 200 alleles are dominant alleles, then what percentage of the alleles are dominant alleles? A-12% B-40% C-60% D-120% What percentage of the alleles are recessive alleles? E-8% F-40% G-60% H-80% Which of the terms of the Hardy-Weinberg equations represents the frequency of the recessive allele in the gene pool? A-p^2 B-p C-2pq D-q^2arrow_forward
- The allele for long whiskers in mice is dominant over the allele for a short whiskers. In a population of 500 individuals, 25% show the recessive phenotype. How many mice would you expect to be homozygous dominant and heterozygous for the trait?arrow_forwardRabbit's ears can be either short or floppy, where short ears are dominant over floppy ears. There are 653 individuals in a population. 104 rabbits have floppy ears and 549 have short ears. Calculate the frequency of the dominant and recessive alleles and the frequency of individuals with dominant, heterozygous, and recessive genotypes.arrow_forwardIn human population X, consider the simple Mendelian trait for freckles. F is the dominant allele and f is the recessive allele. Individuals who are homozygous dominant (FF) or heterozygous (Ff) for the trait express freckles. Individuals who are homozygous recessive (ff) for the trait do not express freckles. In this population, 30% (0.3) of the alleles are recessive (f) and 70% (0.7) are dominant (F). Q1. Use the Hardy-Weinberg equation to determine the genotype frequencies we should expect in the next generation. Be sure to show your work. Q2. You have collected data on the observed genotype frequencies of the next generation. They are: 60% FF, 30% Ff, and 10% ff. Based on these observations and your expectations, is this trait currently evolving in this population? Why or why not? Show your work.arrow_forward
- Tay–Sachs disease is an autosomal recessive disorder. Among Ashkenazi Jews, the frequency of Tay–Sachs disease is 1 in 3600. Assuming the Ashkenazi population is in Hardy-Weinberg equilibrium, what proportion of the population is expected to be carriers (e.g. heterozygous) for the Tay–Sachs allele?arrow_forwardSixteen percent (16%) of the population is homozygous recessive for a trait. What are the frequencies of the dominant and recessive alleles of that trait?arrow_forwardThe ability to taste the compound PTC is controlled by a dominant allele T, while individuals homozygous for the recessive allele (t) cannot taste PTC. In a population consisting of 500 individuals, 347 are tasters and 153 are non-PTC tasters. Calculate the frequency of the T and t alleles in this population, and frequency of the genotypes. (Please train yourself to use the Hardy-Weinberg equation.)arrow_forward
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