Exam 4: Extensions of Mendelian Genetics

The trait of medium- sized leaves in iris is determined by the genetic condition PP'.Plants with large leaves are PP,whereas plants with small leaves are P'P'.A cross is made between two plants each with medium- sized leaves.What is the term for this allelic relationship?

With which of the following would hemizygosity most likely be associated?

Which of the following is an example of codominance?

Two forms of hemophilia are determined by genes on the X chromosome in humans.Assume that a phenotypically normal woman whose father had hemophilia is married to a normal man.What is the probability that their first daughter will have hemophilia?

A condition in which one gene pair masks the expression of a nonallelic gene pair is called________ .

The following coat colors are known to be determined by alleles at one locus in horses: palomino = golden coat with lighter mane and tail cremello = almost white chestnut = brown The following table gives ratios obtained in matings of the above varieties: Assign gene symbols for the genetic control of coat color on the basis of these data.

With ________ ,there will be more than two genetic alternatives for a given locus.

Which of the following is an example of sex- limited inheritance?

A mutation in a gene often results in a reduction of the product of that gene.The term for this type of mutation is ________.

Assume that a dihybrid cross AaBb × AaBb is made in which the gene loci are autosomal,independently assorting,and incompletely dominant.What phenotypic ratio would you expect from such a cross?

When two squash plants with disc- shaped fruit are crossed,depending on the genotype of the parents,disc,sphere,and long fruits may be seen in the offspring.This is an example of ________ .

The following F₂ results occur from a typical dihybrid cross: If a double heterozygote AaBb is crossed with a fully recessive organism aabb,what phenotypic ratio is expected in the offspring?

Which of the following crosses would indicate that the mutants were in the same complementation group?

Typical ratios resulting from epistatic interactions in dihybrid crosses would be________ .

A mutant gene that produces brown eyes bw is located on chromosome #2 of Drosophila melanogaster,whereas a mutant gene producing bright red eyes,scarlet st ,is located on chromosome #3.Phenotypically,wild- type flies with dull red eyes ,whose mothers had brown eyes and whose fathers had scarlet eyes,were mated.The 800 offspring possessed the following phenotypes: wild type dull red ,white,scarlet bright red),and brown.Most of the 800 offspring had wild- type eyes,whereas those with white eyes were the least frequent. From the information presented above,how many white- eyed flies would you expect in the F₂ generation?

Which of the following is true about X- linkage?

Assume that a cross is made between two organisms that are both heterozygous for a gene that shows incomplete dominance.What phenotypic and genotypic ratios are expected in the offspring?

The ABO blood group locus in humans provides an example of ________ .

A ________ ratio indicates incomplete dominance.

A snapdragon plant has red,pink,or white flowers,inherited in an incomplete dominance pattern.It can come in tall or dwarf homozygous recessive varieties.What is the ratio expected if you cross a pink tall heterozygous plant with a pink short plant?