Exam 1: Mendels Principles of Heredity

Which of the following diseases show pleiotropism?

Several single-gene disorders are more common in some populations of people than in others.

Which of the following is not a phenotypic description of allele interactions affecting the expression of traits?

When a late blooming pea and an early blooming pea are crossed and an intermediate phenotype occurs,this result would suggest incomplete dominant inheritance.

In corn,three dominant genes are necessary for aleurone colour.The genotype B_D_R_ is coloured.Any homozygous recessive for one gene is colourless.Predict the genotypes and phenotypes of the offspring of the cross BbDdRR × BbDdRR

Another name for a normal gene is

You wish to know the genotype of some carrot plants that you have grown in your garden so that you might grow more of them.They have reddish orange flesh,are sweet in taste,long in root,and short in leaf.Using classical genetic techniques how would you determine the genotype?

Assume that in guinea pigs,dark brown fur (B)is dominant to black fur (b).If you mate a black guinea pig with a homozygous brown guinea pig,what proportion of the progeny will be homozygous?

The phenotypic ratio 9:3:4 may indicate

A man with blood type A whose father was blood type O married a woman of blood type B whose mother was blood type O.What are the possible blood types of their offspring?

Sickle cell anaemia is a recessive trait in humans.The gene that causes this disease is not located on the sex chromosomes.In a cross between a father who has sickle cell anaemia and a mother who is heterozygous for the gene,what is the probability that their first three children will have the normal phenotype?

Which of the following statements about continuous traits is not true?

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

Stem colour of tomato plants is known to be under the genetic control of at least one pair of alleles such that A_ results in the production of anthocyanin pigment (purple stem).The recessive genotype aa lacks this pigment and hence is green.The production of two locules (seed chambers)in the tomato fruit is controlled by the dominant allele M,and multiple locules is determined by mm.Determine the genotypic and phenotypic ratios of the F₁ from a cross between an inbred tomato plant with a purple stem and fruit with two locules crossed to a tomato plant with a green stem and fruit with multiple locules.

Which of the following phenotypic ratios show incomplete dominance?

In epistasis,one gene's alleles mask the effects of another gene's alleles.

The following five mothers, (a)through (e),with phenotypes given,each produced one child whose phenotype is described as to blood group (A,B,O),M or N antigens,and Rh factor.For each child,select as the father,one of the five males whose genotypes are given.For some children,more than one male may be a possible father. (ii = Type O blood,rr = rh & R = rh⁺]

The pedigree shown is for a human genetic disease in which solid colour indicates affected individuals.Affected individuals in the pedigree are homozygous for the allele that causes the trait.Apply the laws of probability and calculate the probability,the offspring of the cousin marriage (individual 2 × individual 3)will exhibit the disease.

If the parents of a family already have two boys,what is the probability that the next two offspring will be girls?

Which of these is not an example of a continuous trait?