Meiosis/NDJ
These pairs of chromosomes carry the same genes but may have different alleles
What are homologous chromosomes?
This principle states that the two alleles of a gene separate equally into gametes.
What is the principle of segregation?
In X-linked recessive inheritance, affected fathers pass the allele to this group of offspring, who become carriers.
What are all their daughters?
When crossovers happen in two separate regions of a chromosome during meiosis, this event has occurred
What is a double crossover?
Traits influenced by multiple genes, each with a small effect, are described by this term.
What are polygenic traits?
Homologous chromosomes fail to separate
What is Non-dsijunction?
This principle explains how alleles of different genes are distributed during gamete formation.
What is the principle of independent assortment?
A father is affected by an X-linked dominant disorder. Predict the probability his sons and daughters will inherit the trait.
What is 0 percent of sons and 100 percent of daughters?
This means that genes are 10 map units away
What is 10% recombination frequency?
This value measures the proportion of phenotypic variation in a population that is due to genetic variation.
What is heritability?
When nondisjunction occurs in meiosis II, this fraction of gametes will have the correct chromosome number
What is one-half (50%)
In a dihybrid cross AaBb × AaBb, how many offspring are expected to show both recessive traits if the genes assort independently?
What is 1/16?
In a pedigree, an unaffected couple has an affected child. The simplest explanation for this pattern is that both parents have this genotype.
What are heterozygous carriers?
If A–B = 12% and B–C = 8%, this is the most likely order of the three genes
What is A–B–C?
A certain plant’s height varies widely even among genetically identical individuals. This variation is most likely due to this factor.
What is environmental influence?
These fail to separate during meiosis I (A) while (B) occurs during meiosis II
What is homologous chromosomes (A) and sister chromatids (B)
When a son is affected by a recessive condition but both parents appear unaffected, the trait most likely follows this inheritance pattern
What is X-linked recessive?
In a family with an X-linked recessive trait, an unaffected daughter of an affected father and unaffected mother has what probability of being a carrier?
What is 100 percent?
Two genes show a recombination frequency of 10%. Out of 1000 offspring, how many are expected to be recombinant?
What is 100 offspring?
In hydrangeas, flowers are blue in acidic soil and pink in basic soil. This is an example of what phenomenon?
What is phenotypic plasticity (gene–environment interaction)?
No individual mating in the pedigree will have that bring that allele with them
What is a rare mutation?
In snapdragons, red (R) × white (r) = pink (Rr). Two pink plants are crossed. What percentage of the offspring are pink?
What is 50 percent?
A rare disease appears in 2 of 4 children, one male and one female, born to unaffected parents. The parents are not related. Which inheritance pattern is most consistent with this observation?
What is autosomal recessive?
In a testcross between Ab/aB and ab/ab, the recombinant classes appear at 8 %. What is the map distance between the two genes?
What is 8 map units?
Explain why recombinant offspring appear less frequently than parental (non-recombinant) types
What is crossing over occurs only occasionally between linked genes, so fewer gametes contain recombinant chromosomes than parental ones?