Exam 14: Patterns of Inheritance

An individual with an SRY gene is a male mammal.

The frequency of crossing over varies along the length of the chromosome.

Eyelash length is an inherited trait.In the human population,there is an eyelash length gene.There are two possible variants of this gene - an allele for long eyelashes (> 1cm)and an allele for short eyelashes (1 cm or less).How many eyelash length alleles does an individual have in one of her/his somatic cells?

A man with pattern baldness and a woman who has no baldness have a son who develops pattern baldness.Their son has a daughter who also develops pattern baldness.They determine that her expression of this trait is not a symptom of a medical condition.If her mother does not have pattern baldness,the daughter's genotype is ________ and her mother's genotype is ________.

Shown below is a map of five genes,E,L,V,I,and S,on a chromosome.The map units between each gene are shown (map units are a measure of the distance between two genes on a chromosome).Which of the following pairs would have the highest frequency of recombination? E----5----L-2-V-------10-------I--------------20---------------S

A human cell with a Barr body always comes from a female.

In biparental inheritance,paternal and maternal gametes provide chloroplasts to the zygote.

In wolves,gray coat color (G)is dominant to black (g)and brown eyes (B)are dominant to blue (b).The genes that control these traits are located on different chromosomes.The alpha male of the pack has the dominant phenotype for both traits and is heterozygous for both traits.The alpha female has brown eyes and a black coat;she is heterozygous for eye color.Which option represents gametes that would be made by the alpha female?

Type 1 fucosidosis is a rare human disease.Patients cannot hydrolyze the disaccharide fucose,and as a result have severe neurological decline and die by age 6.The disease is due to a defect in the gene that encodes the lysosomal enzyme that breaks down fucose ( $\alpha$ -1-fucosidase),and is inherited in an autosomal recessive manner.Jane and John have a child who has Type 1 fucosidosis.What is the probability that their next child will also have the disease?

Hemophilia is a sex-linked recessive condition that results in deficient blood clotting.The disease causes excessive bleeding which occurs spontaneously or upon slight injury.In dogs (as in humans)hemophilia is caused by a defect in a gene on the X chromosome.What will be the results of mating between a normal,non-carrier female dog and a male dog with hemophilia?

A modification of a gene or chromosome that occurs during gamete formation or early development that permanently alters the expression of that gene for the lifetime of the individual is called

The sex of all animals is determined by chromosomes.

You examine the chromosomes from a somatic cell nucleus of a human individual.That nucleus contains a Y chromosome and a Barr body.Which of the following is ACCURATE?

Roberts Syndrome is an extremely rare genetic disorder that is characterized by mild to severe prenatal retardation or disruption of cell division,leading to malformation of the bones in the skull,face,arms,and legs.Shown below is a pedigree for a family with Robert's Syndrome.Based on this pedigree what mode of inheritance does Roberts Syndrome exhibit?

Adrenoleukodystrophy (ALD)is a fatal disease that results from the inability of liver cells to transport very long chain fatty acids (VLCFAs)across the peroxisomal membrane.It is diagnosed by the presence of high levels of VLFCAs in the blood.The disease results in destruction of brain myelin leading to progressive cognitive impairment,coma,and death by the age of 14.ALD is an X-linked recessive condition,and there has never been a case of ALD described in girls.You have just started your internship at the Mayo clinic and a 10-year-old girl comes in who is in a coma and having seizures.Blood tests show she has extremely elevated levels of long-chain fatty acids.This looks like ALD,but a girl has never been afflicted.When you go to your supervisor to give your diagnosis,which of the following hypotheses do you present to support it?

The two-factor crosses performed by Mendel support the observation that

Roberts Syndrome is an extremely rare genetic disorder that is characterized by mild to severe prenatal retardation or disruption of cell division,leading to malformation of the bones in the skull,face,arms,and legs.Shown below is a pedigree for a family with Robert's Syndrome.What is the genotype of individual II-C? (R = wild type;r = Robert's syndrome)

In humans,having dimples in the cheeks is a dominant trait.If a child has dimples but only one of her parents does,what are the genotypes of her parents? (D = dimples;d = no dimples)

Tay Sachs is a lysosomal storage disease that is inherited in an autosomal recessive manner.Individuals with Tay Sach have a defect in the gene encoding hexosaminidase A,a lysosomal enzyme that breaks down cell membrane components called gangliosides.The inability to break down gangiosides causes harmful quantities of this lipid to accumulate in nerve cells of the brain,eventually leading to premature death of affected cells.There is no known cure for the disease,and death usually occurs by age 4.(T= dominant allele;t = recessive allele)Jack and Jill have a child who has Tay-Sachs.What do you know about the genotypes of Jack and Jill?