Exam 3: Mendelian Genetics

Assume that a black guinea pig crossed with an albino guinea pig produced five black offspring. When the albino was crossed with a second black guinea pig, four black and three albino offspring were produced. What genetic explanation would apply to these data?

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?

For the purposes of this question, assume that being Rh+ is a consequence of D and that Rh - individuals are dd. The ability to taste phenylthiocarbamide (PTC) is determined by the gene symbolized T (tt are nontasters). A female whose mother was Rh - has the MN blood group, is Rh+, and a nontaster of PTC, and is married to a man who is MM, Rh -, and a nontaster. List the possible genotypes of their children. Assume that all the loci discussed in this problem are autosomal and independently assorting.

Assume that a Chi -square test was conducted to test the goodness of fit to a 3:1 ratio and that a Chi -square value of 2.62 was obtained. Should the null hypothesis be accepted? How many degrees of freedom would be associated with this test of significance?

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 which organism did this person work?

In peas, gray seed color is dominant to white. For the purposes of this question, assume that Mendel crossed plants with gray seeds with each other and the following progeny were produced: 320 gray and 80 white. a() What is the most probable genotype of each parent? b() What genotypic and phenotypic ratios are expected in the progeny of such a cross?

A gene can have a maximum of two alleles.

Under what conditions does one expect a 9:3:3:1 ratio?

Assuming a typical monohybrid cross in which one allele is completely dominant to the other, what ratio is expected if the F1s are crossed?

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

Assume that in a series of experiments, plants with round seeds were crossed with plants with wrinkled seeds and the following offspring were obtained: 220 round and 180 wrinkled. a() What is the most probable genotype of each parent? b() What genotypic and phenotypic ratios are expected? c() Based on the information provided in part (b), what are the expected (theoretical) numbers of progeny (400 total) of each phenotypic class?

A 9:3:3:1 phenotypic ratio is expected from a dihybrid cross between a double heterozygote and a fully recessive organism.

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

Assume that a Chi -square test provided a probability value of 0.02. Should the null hypothesis be accepted?

The fundamental Mendelian process that involves the separation of contrasting genetic elements at the same locus is called _.

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, could all the children have normal hearing? Explain your answer.

Which of the following groups of scientists were influential around the year 1900 in setting the stage for our present understanding of transmission 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 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?

In what ways is sample size related to statistical testing?