Exam 13: Chromosomes, mapping, and the Meiosisinheritance Connection

How did the development of anonymous markers aid in the production of a human genetic map?

Huntington's disease is caused by a single dominant allele.It is a lethal disease,yet it persists in the human population.Which of the following statements best describes why?

In some human populations,the proportion of individuals who are heterozygous for the sickle cell allele is much higher than would be expected by chance alone.Why?

Genetic maps are based on recombination frequencies.Because both odd and even numbers of crossovers can occur between any two gene loci,as the physical distance between two loci increases,the maximum recombination frequency levels off at 50%.However,suppose you discovered a species where only an even number of crossovers can occur between any two gene loci.In this case,as the physical distance between two loci increases,you would expect the maximum recombination frequency to

In humans,hemophilia is caused by a recessive allele on the X chromosome.Suppose a man with hemophilia has children with a healthy woman whose mother had hemophilia.What is the probability that their second child will have hemophilia? (Enter the probability as a percent.Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

Traits that are controlled by genes located on the X chromosome are said to be ________.

Nondisjunction of a single pair of autosomes can lead to all of the following except

In humans,individuals with trisomy of the ________ chromosome are most likely to survive until adulthood.

Why isn't mitochondrial DNA a unique identifier?

If a human female has 2 Barr bodies per cell,it is almost certain that

In sickle cell anemia,the defective hemoglobin differs from the normal hemoglobin by

In Drosophila,the allele red eyes (bw+)is dominant to the allele for brown eyes (bw).At another gene locus on the same chromosome,the allele for thin wing veins (hv+)is dominant to the allele for heavy wing veins (hv).Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F₁ progeny. -Given that these two gene loci are very closely linked,the phenotypic ratio in the F₂ generation should be closest to

In humans,if nondisjunction led to an individual with a genotype of XXY,that person would

The geneticist who discovered the white eye mutation in Drosophila and helped establish that genes are carried on chromosomes was

Which offspring inherit all their mitochondrial DNA from their mother and none from their father?

The most common fatal genetic disorder of Caucasians is

In Drosophila,the allele red eyes (bw+)is dominant to the allele for brown eyes (bw).At another gene locus on the same chromosome,the allele for thin wing veins (hv+)is dominant to the allele for heavy wing veins (hv).Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F₁ progeny. -Given that these two gene loci are very closely linked,the genotypic ratio in the F₂ generation should be closest to

In fruit flies (Drosophila melanogaster)there is a dominant allele for red eyes and a recessive allele for white eyes.These alleles are located on the X chromosome.If a heterozygous red-eyed female is mated with a white-eyed male,what percentage of the offspring are expected to be white-eyed females? (Enter the number only without the percent sign.For example,enter 100% as 100 and enter 12.5% as 12.5)

A deletion of a particular stretch of chromosome 15 can cause either Prader-Willi syndrome or Angelman syndrome,depending on

In humans,if an XY individual had a deletion of the SYR gene,that person would