A mutation in a gene often results in a reduction of the product of that gene. The term for this type of mutation is ________. |
loss of function or null (in the case of complete loss) |
A gain-of-function mutation _______. |
results in an increased quantity of the normal gene product |
Typically, when one wishes to represent a gene, the symbol used is _________. |
in italics |
Which of the following symbols indicates a wild-type allele? |
+ |
Part A: Assume that a cross is made between two organisms that are both heterozygous for a gene that shows incomplete dominance. What genotypic ratio is expected in the offspring? Part B: What phenotypic ratio is expected in the offspring? |
A: 1:2:1 B: 1:2:1 |
A situation in which there are more than two alternative forms of a given gene would be called ________. |
multiple alleles |
Why is it necessary to survey a large number of individuals to study multiple alleles? |
Any individual diploid organism can have, at most, two different alleles at a single locus. |
In a mating between individuals with the genotypes I^AI^B × ii, what percentage of the offspring would be expected to have the O blood type? |
0% |
Part A: Determining relationships between alleles Part B: Crossing the forked and pale mutants Part C: Crossing the forked and twist mutants Part D – Assigning genotypes for codominant alleles |
A: twist- The mutant allele is dominant to its corresponding wild-type allele forked- the mutant allele is dominant to its corresponding wild-type allele pale- The mutant allele is neither dominant nor completely recessive to its corresponding wild-type allele B: a- PP b- F_ c- Pp d- F_ e- pp f- F_ g- PP h- f^+f^+ i- Pp j- f^+f^+ k- pp l- f^+f^+ C: The forked mutation and the twist mutation are codominant alleles of the same locus. D: F^TF^T. FF. FF^T |
Part A: What would be the expected frequency of agouti brown offspring in the litter? Part B: Lethal alleles and epistasis Part C: The effect of a third gene on fur color Part D: The effect of a fourth gene on fur color |
A: 3/16 B: 2/3 C: albino, agouti brown agouti black, solid color, black albino, albino D: 9/256 |
Part A: Crossing lines with the same recessive phenotype Part B: Crossing lines with dissimilar recessive phenotypes Part C: A second cross between lines with dissimilar phenotypes Part D: Assembling a genetic model |
A: 1. true 2. independent assortment 3. 9:7 4. complementary gene action B: 1. false 2. failure to complement 3. 3:1 4. complete dominance C: 1. true 2. independent 3. 9:3:4 4. recessive epistasis D: a- aa b- VV c- AA d- vv e- Aa f- Vv g- wild type h- white i- white j- white k- AA l- vv m- a^Ya^Y n- VV o- Aa^Y p- Vv q- wild type r- yellow s- white t- white |
Part A : The inheritance of a skin condition in humans Part B: A sex-linked gene for eye color in Drosophila Part C: The inheritance of both a sex-linked trait and an autosomal trait in humans |
A: X-linked dominant B: all wild type all wild type all wild type 1/2 wild type, 1/2 vermillion C: 1/4 1/2 0 1 |
Part A – Construct a pedigree Part B: Identify the mode of inheritance Part C: Predicting the probability of inheritance Part D: Genetic testing |
A: I. Hanna’s father, Harry’s father II. Hilda, Hope, Holly, Hanna, Haryy III. Jen, Joe, Jane, John IV. Les, Lee, Leah(ONLY RED CIRCLE) B: autosomal recessive C: 1/4 (because they are both heterozygotes) D: newborn screening (either assaying for the GALT enzyme or measuring excess galactose in the newborn’s blood) |
What is the blood type of individuals who cannot add the terminal sugar to the H substance? |
O |
What term is used to express the idea that several genes exert influence over the same characteristic? |
gene interaction |
Alleles that are masked by an epistatic locus are said to be hypostatic to the genes at that locus. |
True |
What would be a typical phenotypic monohybrid ratio in which a lethal allele is involved? |
2:1 |
A gene in which a male heterozygote has a different phenotype compared to a female heterozygote is referred to as __________. |
sex-influenced |
Some genes can be silenced so that they are not expressed depending on the sex of the parent from whom the gene is inherited. This phenomenon is known as __________. |
imprinting |
The white-eye gene in Drosophila is recessive and sex-linked. Assume that a white-eyed female is mated to a wild-type male. What would be the phenotypes of the offspring? |
wild type females, white-eyed males |
BIOL 2300 MasteringGen Ch. 4
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