Exam 3: Mendelian Genetics

Albinism,lack of pigmentation in humans,results from an autosomal recessive gene (a).Two parents with normal pigmentation have an albino child.What is the probability that their next child will be an albino girl?

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?

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

How many different kinds of gametes can be produced by an individual with the genotype AABbCCddEₑFf?

Albinism,lack of pigmentation in humans,results from an autosomal recessive gene (a).Two parents with normal pigmentation have an albino child. a) What is the probability that their next child will be albino? b) What is the probability that their next child will be an albino girl? c) What is the probability that their next three children will be albino?

Name the single individual whose work in the mid-1800s contributed to our understanding of the particulate nature of inheritance as well as the basic genetic transmission patterns.With what organism did this person work?

Albinism,lack of pigmentation in humans,results from an autosomal recessive gene (a).Two parents with normal pigmentation have an albino child.What is the probability that their next child will be albino?

Assuming no crossing over between the gene in question and the centromere,when do alleles segregate during meiosis?

How many kinds of gametes will be expected from an individual with the genotype PpCcTTRr?

According to Charles Darwin and Alfred Wallace,variations followed a more continuous pattern.According to Mendel's model,variation due to dominance-recessive relationships followed a more ___________ form.

A gene can have a maximum of two alleles.

Provide simple definitions that distinguish segregation and independent assortment.

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

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.

Which types of phenotypic ratios are likely to occur in testcrosses when dealing with two gene pairs for which all the genotypic combinations are of equal viability?

What conditions are likely to apply if the progeny from the cross AaBb × AaBb appear in the 9:3:3:1 ratio?

Assuming complete dominance,a 3:1 phenotypic ratio is expected from a monohybrid sib or self-cross.

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?

The autosomal (not X-linked)gene for brachydactyly,short fingers,is dominant to normal finger length.Assume that a female with brachydactyly in the heterozygous condition is married to a man with normal fingers.What is the probability that a) their first child will have brachydactyly? b) their first two children will have brachydactyly? c) their first child will be a brachydactylous girl?

Polydactyly is expressed when an individual has extra fingers and/or toes.Assume that a man with six fingers on each hand and six toes on each foot marries a woman with a normal number of digits.Having extra digits is caused by a dominant allele.The couple has a son with normal hands and feet,but the couple's second child has extra digits.What is the probability that their next child will have polydactyly?