Exam 1: Mendels Principles of Heredity

AA and Aa make red flowers,and aa makes white flowers.BB and Bb make tall plants,and bb makes short plants.What would be the expected ratios of phenotypes among the offspring of the cross of AaBb x aaBb? Note the genotypes in the cross carefully.Assume independent assortment of each gene.

Which of the crosses listed below will give a 1:1:1:1 genotypic ratio in the F₁ generation? Assume independent assortment.

If two or more forms of the same gene exist,the different forms are called

Genes A and B are required for colour.If A or B is absent (that is,aa or bb)the result is colourless.Give the genotypes and phenotypes for each F₁ and F₂ progeny of the cross aaBB × aabb

A dominant trait,Huntington disease,causes severe neural/brain damage at approximately age 40.The gene that causes this disease is not located on the sex chromosomes.A female whose mother has Huntington disease marries a male whose parents are normal.It is not known if the female has the disease.Assuming the female's mother was a heterozygote,and her father was normal,what is the probability that their firstborn will inherit the gene that causes Huntington disease?

Which of the following ratios indicates a lethal gene?

The actual alleles present in an individual make up the individual's

The first generation of offspring from the parents is called

How does penetrance differ from expressivity?

Which of the following terms is not a type of mating cross?

A science teacher is attempting to convince her class that alcoholism,which has long been known to be a disease of polygenic inheritance,really is partially genetically determined.You are asked to assist in the design of an experiment that will help show eighth graders genetic transmission of differences in alcohol drinking.You have been given outbred rats as your experimental model.Set up a quantitative experiment that would test the hypothesis that alcoholism,as determined by amount of alcohol drunk,is a quantitative trait.

What are the four general themes that have arisen from Mendel's work?

Genes with more than one wild-type allele are termed polymorphic.

Which of the following ratios demonstrate gene interaction?

A _____________ results whenever the nucleotide sequence is changed.

Below is a pedigree for a human trait.Shaded symbols are for individuals exhibiting the trait.Identify the mode of inheritance of the trait and apply the laws of probability to calculate the probability that individual #4 is a heterozygous carrier of the trait.

In a dihybrid cross for which the parental cross is AABB × aabb,what proportion of F₂ offspring will be heterozygous for both genes? Assume independent assortment.

You have obtained an interesting flower for your garden from your neighbour.The neighbour has given you two pure lines of the plant,one with red flowers and one with yellow flowers.You decide to cross them and find that you obtain all orange flowers.The curious molecular geneticist in you decides to test two independent hypotheses: Hypothesis 1: Incomplete dominance;Hypothesis 2: Recessive epistasis.The first step in your test is to self the F₁ orange plants,which you complete only to find that the results do not statistically distinguish the two hypotheses.a)What ratio of yellow,orange,and red would you expect in the F₂ population for each hypothesis and b)what crosses would you complete next to definitively test your two hypotheses?

If two homozygous recessive mutants show the same phenotype,but are caused by mutations at different loci,what will be the phenotype ratio among their F₁ progeny?

Which of the following phenotypic ratios show independent assortment?