Inheritance
Sex
Multiple genes and Lethals
Pedigrees
Quantitative Genetics
100
An individual has the genotype RrGg. What possible gametes can they form, assuming these genes are unlinked?
What is: RG, Rg, rG, rg
100
An autosomal trait that is only expressed in one sex or the other is:
What is sex-limited
100
A diploid individual will have how may alleles for a single gene?
What is : 2, one inherited from each parent
100
What features will separate a dominant and recessive inheritance pattern?
What is: Recessive inheritance will be able skip generations (affected children with no affected parents)-- dominant inheritance patterns will never skip generations (affected children *always* have at least one affected parent). For rare recessive traits, inbreeding is common.
100
What does this equation give you h^2 = VA/VP
what is narrow sense heritability
200
A single gene with multiple phenotypes is:
What is pleiotropy
200
A sex-influenced trait
What is: An autosomal gene that is expressed differently in one sex vs another (e.g. dominant in males, recessive in females, or vice versa)
200
When multiple genes interact, leading to the genotype of one gene influencing the phenotype of another:
What is : epistasis
200
In this inheritance pattern, affected mothers pass the trait down to all progeny. Affected fathers never pass the trait down to progeny.
What is: Mitochondrial inheritance (frequently cytoplasmic inheritance)
200
Apart from additive genetic variation, what OTHER kinds of variation contribute to VG?
What is dominance and epistasis
300
How do segregation and independent assortment relate to mendelian inheritance?
What is: Independent assortment: Offspring inheriting alleles for one gene will not influence the likelihood of them inheriting alleles for another (assuming no linkage) Segregation: generally progeny only inherit one allele for a gene from each parent (one homologous chromosome)
300
Queen is a carrier for hemophilia (x linked recessive), married to King, who is affected by hemophilia. They have three unaffected children. What's the probability that all three of them are carriers?
What is 1/2 * 1/2 * 1/2
300
Yellow is dominant over brown fur in mice. However, you cannot isolate a true-breeding yellow line-- crosses of yellow mice always produce some brown progeny. Why?
Yellow color is likely lethal. You can only insure a true breeding phenotype when a gene is homozygous for a trait. If the homozygote is lethal, you only see heterozygotes for a the trait in question.
300
What features distinguish x-linked recessive inheritance from autosomal recessive inheritance?
What is:Both will skip generations. X linked recessive traits will be more common in men than women. An affected woman MUST have an affected father, and a mother who is either affected or a carrier. Men will always inherit these conditions from their mothers, not their fathers. Autosomal recessive traits will be equally likely to affect men and women. Affected individuals must have two parents who are either affected themselves, or carriers.
300
What is the difference between broad sense and narrow sense heritability?
What is: broad sense heritability is the percentage of phenotypic variance in a population due to genetic factors. narrow sense heritability is the percentage that can specifically be passed from parent to offspring (additive genetic variance)
400
What is the relationship between homologous chromosomes, and alleles?
What is: The maternal and paternal chromosomes in a homologous pair have the same genes at the same loci, but possibly different alleles. E.g., a person might have a blue-eye allele from one parents on one chromosome, and a brown-eye allele from the other parent on the homologous chromosome.
400
What are four forms of sex determination
XX and XY (where heterogametic sex is male) ZZ and ZW (where heterogametic sex is female) XX and XO (where females have two sex chromosomes, and males have only one-- are haploid for sex chromosomes) Environmental (where sex is determined by temperature, or other environmental factors) Haplo-diploid(where one sex is diploid, and the other is haploid-- e.g. bees and ants females are diploid, males haploid)
400
In sweat peas, genes C and P are necessary for purple flowers. In the absence of either or both (ccpp) genes, the flowers are white. In a cross between Ccpp and CcPp, what are the expected phenotypic proportions of offspring?
What is: 5 white: 3 purple
400
What features would distinguish a Y-linked trait?
What is: This trait would only be present in men. It would be passed from father to son.
400
Many life history traits (fecundity, lifespan, etc.) have a heritability close to 0. Why do you think this is the case?
What is traits that are very important tend to be fixed at the highest fitness combination of alleles, and not variable due to heritable genetics--> no genetic variation for the trait in the population
500
What is the difference between germ cells and somatic cells?
What is : germ cells are sex cells (eggs and sperm), haploid, products of meiosis somatic cells are non-sex cells, diploid, and the product of mitosis
500
You want to do an experiment to determine if red eyes (dominant) vs white eyes (recessive) is sex-linked in Drosophila. What experiment do you do? What kind of result do you get?
What is Reciprocal cross Red eyed true breeding male crossed to white eyed female: all male offspring are white eyed, all female offspring are red eyed White eyed true breeding male crossed to red eyed female: All male offspring are red eyed, all female offspring are red eyed
500
You self-cross an organism with the genotype AaBbCcDdEe. What fraction of progeny do you expect to be homozygous recessive for all five genes?
What is: (1/4)^5
500
Queen is a carrier for hemophilia (x linked recessive), married to King, who is affected by hemophilia. Their first child, Princess, is unaffected. However, several of Princess's children ARE affected. What is the probability that Princess is a carrier?
What is 100%
500
Natural selection can only act on traits that have a narrow sense heritability higher than 0. Why might this be the case, in the context of the breeders equation?
What is: Natural selection can only occur when a trait has a fitness advantage (which means the breeders will have a mean value different than the population average), and it only matters if it can be passed to the next generation. Dominance interactions cannot be transmitted, and neither can environmental effects.
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