Exam 3: Mendelian Genetics

What are two typical ratios that result from crossing heterozygotes with homozygous organisms?

Assume that you have a garden and some pea plants have solid leaves and others have striped leaves. You conduct a series of crosses [(a) through (e)] and obtain the results given in the table. Define gene symbols and give the possible genotypes of the parents of each cross.

According to Mendel's model, because of ________, all possible combinations of gametes will be formed in equal frequency.

A certain type of congenital deafness in humans is caused by a rare autosomal dominant gene. In a mating involving a deaf man and a deaf woman (both heterozygous), would you expect all the children to be deaf? Explain your answer.

Under what conditions does one expect a 1:1:1:1 ratio?

Which phenotypic ratio is likely to occur in crosses of two completely dominant, independently segregating gene pairs when both parents are fully heterozygous?

The phenotype of vestigial (short) wings (vg) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive gene for hairy (h) body. Assume that a cross is made between a fly with normal wings and a hairy body and a fly with vestigial wings and normal body hair. The wild -type F1 flies were crossed among each other to produce 1024 offspring. Which phenotypes would you expect among the 1024 offspring, and how many of each phenotype would you expect?

In studies of human genetics, usually a single individual brings the condition to the attention of a scientist or physician. When pedigrees are developed to illustrate transmission of the trait, what term is used to refer to this individual?

In a Chi -square test, as the value of the ç2 increases, the likelihood of rejecting the null hypothesis _.

Which types of phenotypic ratios are likely to occur in crosses when dealing with a single gene pair for which all the genotypic combinations are of equal viability?

A recessive allele in tigers causes the white tiger. If two normally pigmented tigers are mated and produce a white offspring, what percentage of their remaining offspring would be expected to have normal pigmentation?

Provide simple definitions that distinguish segregation and independent assortment.

Tightly curled or wooly hair is caused by a dominant gene in humans. If a heterozygous curly -haired person marries a person with straight hair, what percentage of their offspring would be expected to have straight hair?

Dentinogenesis imperfecta is a rare, autosomal, dominantly inherited disease of the teeth that occurs in about one in 8000 people (Witkop, 1957). The teeth are somewhat brown in color, and the crowns wear down rapidly. Assume that a male with dentinogenesis imperfecta and no family history of the disease marries a woman with normal teeth. What is the probability that a() their first child will have dentinogenesis imperfecta? b() their first two children will have dentinogenesis imperfecta? c() their first child will be a girl with dentinogenesis imperfecta?

To test Mendel's Law of Segregation, the experimenter needs a minimum of two contrasting forms of a gene.

Mendel's Law of Segregation is supported by a 1:1 ratio of offspring when one parent is heterozygous and the other is homozygous recessive.

Assuming independent assortment, what proportion of the offspring of the cross AaBbCcDd × AabbCCdd will have the aabbccdd genotype?

What is the probability of flipping a penny and a nickel and obtaining one head and one tail?