chaper 15.1 and 16 Flashcards
genetic variation
genetic differences that exist among individuals in a population at a particular time
genotype
genetic makeup of a cell or organism
polymorphism
refers to any genetic differences among individuals that is sufficiently common that it would almost certainly be present in a group of 50 randomly chosen individuals
phenotype
an individual’s observable characteristics or traits
alleles
different form of any gene
homozygous
an individual that inherits an allele of the same type from each parent
heterozygous
individuals who inherit different types of allele from each of their parents
genotype-by-environment interaction
a phenotype is the result of an interplay between genes and the environment
neutral mutation
have no effect on the organism, or have effects that are not associated with differences in survival or reproduction
transmission genetics
the manner in which genetic differences among individuals are passed from generation to generation
trait
characteristic of an individual
blending inheritance
traits in the offspring resemble the average of those in the parents
hybridization
interbreeding between two different varieties or species of an organism
true breeding
the physical appearance of the offspring in each successive generation is identical to the previous one
P1 generation
parental generation
F1 generation
first offspring generation
F2 generation
the offspring of the F1 generation
reciprocal crosses
the expressions of the trait in the female and male parents are interchanged
recessive
contrasting trait that does not appear
dominant
the trait that does appear
principle of independent assortment
the principle that segregation of one set of alleles of a gene pair is independent of the segregation of another set of alleles of a different gene pair
Punnett square
a worksheet in the form of a checkerboard used to predict the consequences of a random union of gametes
testcross
any cross of unknown genotype with a homozygous recessive genotype
monohybrid cross
a genetic cross between homozygous individuals but with different alleles for a single gene locus of interest
dihybrid cross
a breeding experiment between parental generation organisms that different in two traits
incomplete dominance
the phenotype of the heterozygous genotype is intermediate between those of the homozygous genotypes
principle of segregation
the principle by which half the gametes receive one allele of a gene and half receive the other allele
probability
the likelihood that a specified genotype will occur
addition rule
the principle that the probability of either of two mutually exclusive outcomes occurring is given by the sum of their individual probabilities
multiplication rule
the principle that the probability of two independent events occurring together is the product of their respective probabilities
linked genes
describes genes that are sufficiently close together in the same chromosome that they do not assort independently
epistasis
genes the modify the phenotypic expression of other genes
pedigree
a diagram of family history that summarized the record of the ancestral relationships among individuals
incomplete penetrance
the individuals with a genotype corresponding to a trait do not actually show the phenotype due to the environment effects or interactions with other genes
variable expressivity
a particular phenotype is expressed with a different degree of severity in different individuals
