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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

Lethal genes in rabbit - pelger anomaly

Pelger anomaly in rabbits involves white blood cell nuclear segmentation. Rabbits homozygous [PP] to this condition are usually still born or die just after birth due to gross illformed skeletal structure. Pelgers are heterozygous [Pp] and normal rabbits are homozygous [pp]. What is the adult F2 phenotypic ratio in all pelger ma

Penetrance in abnormality of eye in flies

A series of crosses in a controlled environment in which all progeny were known to carry a dominant autosomal gene A that causes eye abnormality produced 600 normal flies and 1400 abnormal flies. What is the penetrance of this gene A in this particular experiment?

Blood transfusion is assessed.

A normal person receives blood transfusion from an individual having sickle cell trait. Will this transfusion affect the recipient? Why / why not? Ideas are justified.

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.

Calculating phenotypic ratio in dihybrid crosses is achieved.

In garden peas, yellow seed color is dominant over green, and round seed shape dominant over wrinkled. What phenotypic ratio can be expected in F2 from a cross between pure yellow and round with green and wrinkled? What would be the ratio of yellow: green and round: wrinkled? Ideas are included.

Probability in genetics is the feature topic.

If two heterozygous brown rabbits are crossed, what would be the probability of the first three baby rabbits being brown, white, brown or white, brown, white? Explanations are included.

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

Understanding recombination in bacteria.

A transformation experiment is performed with a donor strain that is resistant to four drugs: A, B, C, D. The recipient is sensitive to all four drugs. The treated recipient-cell population is divided up and plated on media containing various combinations of the drugs. The results are shown in the table below. Drug # co

Potential problems with transgenic mouse strains.

You have created 3 independent mouse strains carrying the same transgene by non-targeted transgenesis. All 3 strains have otherwise identical genetic backgrounds, yet all 3 have different phenotypes. What are potential explanations for this phenotypic variability?

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).

Outlines of types of epistasis are included.