Understanding meiosis for haploid organisms.

Suppose that meiosis occurs in the transient diploid stage of the cycle of a haploid organism of chromosome number "n". What is the probability that an individual haploid resulting from the meiotic division will have a complete parental set of centromeres (that is, a set all from one parent or all from the other parent)?

Understanding Mendelian analysis and heredity.

Holstein cattle are normally black and white. A superb black and white bull, Nick, was purchased by a farmer for $100 000. The progeny sired by Nick were all normal in appearance. However, certain pairs of his progeny, when interbred, produced red and white progeny at a frequency of about 25 percent. Nick was soon removed fr ...continues

Understanding Mendelian heredity.

Maple syrup urine disease is a rare inborn error of metabolism. It derives its name from the odor of the urine of affected individuals. If untreated, affected children die soon after birth. The disease tends to recur in the same family, but the parents of the affected individuals are always normal. What does this information ...continues

Understanding Mendelian heredity.

Huntington's chorea is a rare, fatal disease that usually develops in middle age. It is caused by a dominant allele. A phenotypically normal man in his early twenties learns that his father has developed Huntington's chorea. (a) What is the probability that he will himself develop the symptoms later on? (b) What is the p ...continues

Understanding Mendelian genetic heredity.

When a pea plant of genotype Aa Bb produces gametes, what proportion will be Ab? (Assume that the two genes are independent) (a) 3/4 (b) 1/2 (c) 9/16 (d) none (e) 1/4

Understanding Mendelian genetic heredity

When a fruit fly of genotype Mm Nn Oo is mated to another fly of identical genotypes, what proportion of the progeny flies will be MM nn Oo? (Assume that the three genes are independent) (a) 1/2 (b) 1/8 (c) 3/8 (d) 1/32 (e) 1/64

Understanding Mendelian genetic heredity.

Consider the cross Aa Bb Cc Dd Ee x aa Bb cc Dd ee (a) What proportion of progeny will PHENOTYPICALLY resemble (1) the first parent (2) the second parent (3) either parent (4) neither parent? (b) What proportion of progeny will GENOTYPICALLY resemble (1) the first parent (2) the second parent (3) either pare ...continues

Understanding Mendelian heredity.

Consider two-child families in which the parents have been identified as carriers of an autosomal recessive gene by virtue of having at least one child with the phenotype. When the children of many such two-child families are totaled, what proportion of children in these families will show the phenotype? (Hint: The answer is N ...continues

Recombination in bacteria and in viruses that infect bacteria.

Four E. coli strains of genotype a+ b- are labeled 1,2,3 and 4. Four strains of genotype a- b+ are labeled 5,6,7, and 8. The two genotypes are mixed in all possible combinations and (after incubation) plated to determine the frequency of a+ b+ recombinants. The following results were obtained, where M = many recombinants, L = ...continues

Recombination in bacteria and in viruses that infect bacteria.

In E. coli, four Hfr strains donate the markers shown in the order given: strain 1---Q---W---D---M---T strain 2---A---X---P---T---M strain 3---B---N---C---A---X strain 4---B---Q---W---D---M All these Hfr strains are derived from the same F+ strain. What is the order of these markers on the circular chromosome of ...continues