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Genetics

Test Crosses Examined

I have a phenotypically purple flowered pea plant with the flowers located along the stem. How do I determine the genotypes and do test crosses on the homozygous and heterozygous genotype and determine the genotype and phenotype ratios of each cross? The process is explained.

Population-Genetics Problems using Hardy-Weinberg Equilibrium.

In a particular flower, a single pair of alleles determines the petal color (C). Red flowers have the genotype CR/CR (homozygous for CR), white flowers have the genotype Cr/Cr (homozygous for Cr) and pink flowers have the genotype CR/Cr (they are heterozygous). In a given population, 49 flowers had red petals, 42 had pink pe

Genotypic and phenotypic ratios in hair texture in dogs.

Wire hair in dogs is dominant over its recessive allele for smooth hair. A cross between heterozygous wire haired individuals produces F1 which are then test crossed. Determine from the expected progeny their phenotypic and genotypic ratios.

Lethality in Mexican hairless breed of dogs

Hairless condition in Mexican hairless breed of dogs is heterozygous [Hh] against the normal homozygous recessive [hh]. Puppies homozygous for H allele are born dead due to abnormalities in mouth and absence of external ears. If the average litter size at weaning is 6 in matings between hairless dogs, what is the expected number

Genetics Exercises: 5 Exercises on Crossings- Autosomal and Sex Linked genes

Complete the gene exercise. Refer to attachment. Exercise I We are going to begin by looking at some basic mating patterns, using a couple of eye color mutations in fruit flies. The normal fruit fly has brick red eyes. This is called the "wild type," because the vast majority of wild fruit flies have this co

Helping dyslexic students in and out of the classroom.

What if I have a student that is dyslexic...what are some things that I can do in the classroom, as a teacher to make things easier? Also, what are some tips that I can give the parents and what are some techniques that the school counselor can use when counseling the student?

Bio 100

1. There are three differences between the accomplishments of mitosis and the accomplishments of meiosis. One of these differences is fairly trivial: the other two are very important. What these three differences? For each of the differences, make sure that you clearly explain what it is that mitosis does and what it is that

Determining phenotypic ratio using test crosses

A true-breeding red snapdragon was crossed to a true-breeding white snapdragon. The F1 progeny were pink. When F1 x F1 matings were made, the following F2 progeny were observed. 1850 red 670 pink 831 white Total 3351 a. Using clearly defined genetic symbols, give the appropriate parental, F1 and F2 genotypes in o

Constructing pedigrees to analyze and determine inheritability and probability.

Gaucher disease is caused by a chronic enzyme deficiency that is more common among Ashkenazi Jews than in the general population. A Jewish man has a sister afflicted with the disease. His parents and grandparents, and other three siblings are not affected. Discussions with his relatives in his wife's family reveal that the disea

Mendelian Genetic problems

Could you please take a look at the attached problems that I have done which include Punnett square and genotype. I think I have done the problems correctly but I just need a second set eyes to see if there are any holes in my understanding on this topic.

Understanding eukaryotic chromosome mapping techniques.

In haploid yeast, a cross between arg- ad- nic+ leu+ and arg+ ad+ nic- leu- produces haploid sexual spores, and 20 of these are isolated at random. The resulting cultures are tested on various media as shown below (in the table below, + means growth, while - means no growth). (a) What can you say about the linkage arrangement

Genetics -- map units

EDIT to the problem below: I just realized that the various numbers of offspring add up to 9900, not 10,000, which is the supposed total. So for problem #2, I randomly added 100 to my recombinant numbers and got the answer, 30.1, which turned out to be correct. But the same thing did not work for problem #1. Adding 100 to the

Double Cross-overs

Hi. Can you help me with the following genetics problem, please: "Consider a pair of homologous chromosomes heterozygous for three genes (e.g., ABC/abc) during prophase I of meiosis. Let the sister chromatids of one homolog be numbered 1 and 2 (ABC); and the sister chromatids of the other homolog be numbered 3 and 4 (abc).

The Hardy-Weinberg law states two things:

Background The Hardy-Weinberg law states two things: 1. If no outside forces are acting on the population, then the allele frequency will remain constant from one generation to the next. 2. If no outside forces are acting on the population, then the genotype frequencies will be p^2, 2pq, and q^2. The converses of these sta

Factors Involved When Genetically Modifying A Mouse

Suppose you are given the task of genetically modifying a mouse so that its skin cells secrete a bitter tasting protein that will protect it from predation. What factors would you have to consider in order to achieve this goal? You only need to consider protein targeting, do not be concerned with how you would get the gene int

Probability genes

Assume that a trait is determined by a single pair of genes where one allele is dominant and the other is recessive. In a population, 30% of the females are pure dominant, 60% are hybrid, and 10% are pure recessive. If a pure recessive male mates with a random female and their first offspring has the dominant trait, what is th

Genetics in Auxotrophic Mutation Strains

1 Two new hair dyes A and B were tested in the Ames test. Both were tested with and without liver homogenate. Two auxotrophic strains of bacteria were used, one in which the auxotrophy was caused by a nonsense mutation (mutant 1) and the other by a frameshift mutation (mutant 2). After treatment the cells were plated on minimal

Yeast Cells and Adenine-Requiring Auxotrophs

4. In yeast, wild type colonies are white. Adenine-requiring auxotrophs (ad) are red when grown on medium containing limiting amounts of adenine. This is due to the accumulation of a red precursor in adenine biosynthesis. If cells from an ad strain are plated on minimal medium most cells don't produce colonies but two rare ty

Genetics

(a) Give the genotypes of the two parental goats, showing gene arrangement and gene order. (b) Give the % recombination between each pair of genes. (c) Draw a map showing the positions of all genes and distances between genes, where appropriate (d) Give the formula and calculate the coefficient of coincidence (e) Calcula

Determining haplotypes is achieved.

An autosomal dominant disease (Huntington disease) is being transmitted in the pedigree below. A two-allele marker (designated 1 and 2) has been typed for each family member. What are the mother's haplotypes i.e. which alleles are inherited together? What is the recombination frequency for the marker and the disease locus? What