First Check #6 (tut 14) Flashcards
A gene that affects the expression of a second gene is an example of
epistasis
____ is an example of a character that is controlled by more than one gene (a quantitative character) and demonstrates a continuum of phenotypes.
Polygenic inheritance
The gene controlling ear color in an organism known as a gizmo has two alleles that exhibit incomplete dominance: CR, which codes for red ears; and CY, which codes for yellow ears. Individuals that are homozygous for the CR allele have red ears, whereas the heterozygous genotype produces orange ears. Those that are homozygous for the CY allele have yellow ears. If two individuals with orange ears are crossed, what ratio of phenotypes should be expected in the offspring?
1:2:1 red:orange:yellow ears
Mice with the genotypes BBCc and bbcc are crossed. The alleles for brown coat (b) and no pigment (c) are recessive, and black coat (B) is dominant. What color of mice would NOT be produced by this mating?
brown
An individual that is heterozygous for an allele and that exhibits a phenotype intermediate between that of the two homozygous alternatives is an example of
incomplete dominance
What possible blood types could offspring have if their two parents have the blood types A and AB, respectively?
A, B, and AB only
In water snakes, body color is controlled by two alleles that display incomplete dominance. Snakes with the BB genotype are brown, those with the Bb genotype are gray, and individuals with the bb genotype are green. If a brown snake and a gray snake are crossed, what ratio of phenotypes should be expected in the offspring?
1:1, brown:gray
You are examining a trait which shows three distinct phenotypes, with the phenotype of heterozygotes expressing both alleles seen in the homozygotes. This is an example of:
Codominance.
Pedigrees reveal that a trait shows a dominant pattern of inheritance if that trait generally
did not skip generations
____ is an example of a recessive inherited trait.
Cystic fibrosis
If one parent who has Huntington’s disease is heterozygous for the trait and the other parent is not affected, what are the chances of their offspring inheriting the trait?
50%
If both parents are carriers of an recessive inherited trait, what are the chances that their child will express that trait?
25%
Part complete
The effects of ______________________ can be almost completely overcome by regulating the diet of the individual from infancy.
phenylketonuria (PKU)
In rabbits, the homozygous genotype LCLC has normal legs, LCLc results in deformed legs, and LcLc results in very short legs. The genotype FBFB produces black fur, FBFb brown fur, and FbFb white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur?
25%
Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. The relationship between genes S and N is an example of which of the following inheritance patterns?
epistasis
