Vocabulary
Different forms of a gene (starts with an a)
allele
What percent of offspring would have a recessive phenotype in Aa × Aa?
25%
This dominance pattern shows a blending of traits in heterozygous organisms.
incomplete dominance
Breeding for desired traits over generations
Mendel’s law that states alleles separate during gamete formation
law of segregation
An organism with two of the same alleles
homozygous
Genotype of offspring from AA × aa
heterozygous (all Aa)
This dominance pattern results in both traits being expressed at the same time; they coexist
codominance
Breeding closely related organisms
inbreeding
Two processes that increase genetic variation during meiosis (name one)
1. crossing over
2. independent assortment
The physical appearance of an organism
phenotype
If two heterozygous parents (Aa × Aa) have 4 offspring, how many would you expect to show the dominant trait?
3
A person with blood type AB shows this dominance pattern
codominance
Breeding two organisms with different desirable traits (like hunting + smell in dogs)
hybridization
A diagram used to trace traits through generations
pedigree
dominant
A homozygous recessive organism is crossed with a heterozygous organism (aa × Aa). What percentage of the offspring will show the recessive trait?
50%
Why do X-linked traits appear more often in males?
Males only have 1 X chromosome
A cross used to determine an unknown genotype
test cross
If a trait only appears when two recessive alleles are present, it is
recessive
A person who is heterozygous for a recessive disorder
carrier
Freckles (F) are dominant over no freckles (f).
In a cross where both parents have freckles and are heterozygous, what are the parent genotypes? (looking for the letter combinations)
FfxFf
Two parents with type AB blood have a child—what is the probability (percentage) the child is also AB?
25%
In a test cross, the unknown organism is crossed with what genotype?
homozygous recessive
Why is sickle-cell trait beneficial in some environments?
provides resistance to malaria