Explore BrainMass


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.

Mendelian Genetics

"a" is a dominant mutant allele of the A gene, and "b" is the recessive mutant allele of the B gene. To see the mutant phenotype, one requires either an "a" mutant phenotype or a "b" mutant phenotype (both mutations are not necessary). What would the F2 segregation ratio be (wild type to mutant) of the cross of an aabb mutant

Mendelian Genetics, Punnet squares

You cross an aa bb mutant plant with an AA BB wild type. What would the F2 segregation ratio be (wild type to mutant) if: a.) both mutations, a and b, were recessive? b.) both mutations were dominant? c.) one mutation was dominant and one recessive? (assume both mutations are required for the mutant phenotype) (assume t

Evolution Problems Involving Math are included.

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

Somatic male cells are assessed.

If the somatic cells of a human male were found to contain one Barr body in their nucleus the most likely chromosome makeup of the individual would be: XO XX XYX XXY XXX

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

Meiosis is depicted.

If a child more strongly resembles one parent's physical traits than the other parent's, the explantion could be due to chromosome movements during? A. anaphase II B. metaphase II C. prophase II D. anaphase I E. telophase I This study is discussed.

Genotype crosses are demonstrated.

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring of genotype aa bb cc? A. 1/64 B. 1/32 C. 3/64 D. 1/16 E. 9/64


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 is examined.

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


(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