bio 311d

• The two members of a homologous pair of chromosomes have genes controlling the same kind of characters
• If a cell with genome of 20 homologous pairs of chromosomes undergoes normal meiosis, how many cells result, and how many chromosomes are in each of the resulting cells?

  Four cells, each with 20 chromosomes
• If the diploid number (2n) for a species is 50, how many homologous pairs are in that species’ genome, and how many chromosomes are in a sperm cell of that species ?


  25, 25
• 1. Albinism is a recessive trait. From these two heterozygous parents (who are NOT albino), what fraction of their children are expected to be albino?


  1/4
• 1. In a standard deck of playing cards, four suits exist (red suits=heart & diamonds, black suits=spades & clubs). Each suit has 13 cards. Therefore, 52 cards are in a deck.

  Q: In a single draw, what is the probability that you will draw a red card?

  1/2
• 1. This form of Albinism is inherited as a recessive trait. From these two heterozygous parents (who are NOT albino), what fraction of their children are expected to be albino?


  1/4
• 1. In the mating cross Tt x TT, what is the probability of their offspring having genotype "tt"?

  0
• In the mating cross Tt x TT, what proportion of the offspring of that cross will be heterozygous?

  .5
• 1. One of the two sisters shown here is albino, a simple recessive trait inherited from heterozygous non-albino parents.  What is the probability that the sister with normal coloration is a carrier of the albinism allele?

  .66
• Josh and Ann are planning to have children. Neither has the genetic disease cystic fibrosis (homozygous recessive genotype), but because some individuals in their extended families do have the disease, the couple gets tested to see if they are carriers. Results: Josh is a heterozygous carrier for the recessive  cf allele f. Ann is homozygous for normal F allele

  What percent of their children would be expected to have the disease cystic fibrosis?

  0
• 1. What is the probability that a couple planning to have two children will have two sons ( = probability of a certain combination of two independent events).

  1/4
• 1. A couple with two sons is expecting a new baby - what is the probability it will be a son?

  1/2
• 1. A person with type N (phenotype) would have which genotype?

   L(N) L(N)
• 1. A couple both of whom are heterozygous carriers (Aa) for a recessive allele (a) for albinism plan to have two children. What is the probability that both of their children will be albino?

  1/16
• 1. A mouse shows the dominant black phenotype (complete dominance over the recessive brown fur allele) but has unknown genotype. To do a test cross, you would mate this black individual with which of these?

  any brown mouse
• 1. Which of these sets of parents (blood type phenotype given) is probably not correctly matched to their child (by blood type)

  Parents A and O, child AB
• Pleiotropic alleles affect multiple systems of the persons body
• 1. Manx cats are the heterozygotes for a gene locus where one homozygous condition is embryonic lethal (dies early in development)

  When two Manx cats are mated, the phenotype ratios of their offspring is which?

  2 Manx : 1 normal
• Siamese cat has some parts of the body that are dark and some light because only some of the cells are expressing the genes for dark pigment
• When n is the number of homologous pairs, the number of possible combinations of parental chromosomes in gametes is which? (choose a formula)

  2^n
• independent assortment and crossing over contribute to genetic variability among gametes produced by one parent
• what is the mutation where a sperm with a normal haploid number of chromosomes fertilizes an egg that contains an extra copy of chromosome 21

  trisomy 21 (down syndrome)
• in humans which parent gives the sex-determining trait to the child

  father
• x lined recessive traits are more likely to appear in the phenotypes of males than females because

  males have only one allele for x linked traits
• A woman (who does not have hemophilia) is heterozygous for the recessive X-linked gene for hemophilia. Her husband is not affected by hemophilia. Draw the Punnett Square for this mating.

  1. What proportion of their sons will have hemophilia?

  1/2
• A woman (who does not have hemophilia) is heterozygous for the recessive X-linked gene for hemophilia. Her husband is not affected by hemophilia. Draw the Punnett Square for this mating.7. What proportion of their daughters will be carriers for the hemophilia allele?

  1/2
• 1. The A allele frequency is 0.7 - this means which?

  the proportion of A alleles in the total gene pool
• 1. The AA genotype frequency is is 0.7 – this means?

  B. the proportion of individuals with genotype AA
• 1. There are two alleles for a certain gene locus, A and a. 70% of the alleles in a particular gene pool are A. What is the allele frequency of a ?

  .30
• Within a population of butterflies, the color brown (B) is dominant over the color white (b), and 25% of all butterflies are white.

  1. The value of q is what?

  .50
• Within a population of butterflies, the color brown (B) is dominant over the color white (b), and 25% of all butterflies are white.

  1. The percentage of butterflies in the population that are heterozygous is

  50%
• 1. In the H-W equation  p + q = 1, the term “p” can refer to which?

  frequency of the dominant allele in the gene pool
• 1. In a population of 1000 diploid individuals the gene pool for one trait like eye color would consist of how many alleles?

  2000
• Within a population of butterflies, the color brown (B) is dominant over the color white (b), and 25% of all butterflies are white.4. the percentage of butterflies in the population that are heterozygous is

  50%
• Within a population of butterflies, the color brown (B) is dominant over the color white (b), and 25% of all butterflies are white. 5. The percentage of homozygous dominant individuals is

   25%
• 1. Red short-horned cattle are homozygous for the red allele, white cattle are homozygous for the white allele, and roan cattle are heterozygotes. Population A consists of 36% red, 16% white, and 48% roan cattle. What are the allele frequencies? red and white

  red = 0.6, white = 0.4
• 1. Inbreeding increases the percentage of which genotypes in a population?


  both homozygotes
• 1. Cheetahs formerly ranged widely across sub-Saharan Africa but now are in small isolated populations which have relatively low genetic variability (low heterozygote frequency for many gene loci). Which of the Hardy-Weinberg criteria has changed and may not be met in cheetah populations due to this?

  large population size
• 1. Due to global warming, a river has dried up, allowing two different large populations of rabbits, which were isolated before, to mate with one another. Which of the Hardy-Weinberg criteria has changed for one of those rabbit populations?

  no gene flow
• an individual that produces the most offspring has the highest relative evolutionary fitness