Chapter 12 Flashcards
a specific heritable attribute or property of an organism
character
one of the forms of a genetic character
traits
alternative forms of characters
character differences
fertilization in which sperm nuclei in pollen fertilize egg cells of the same
self-fertilization
fertilization of one plant by a different plant
cross-fertilization/cross-pollination
individual that passes traits without change from one generation to the next
true-breeding
a genetic cross in which the 2 parents are switched with respect to which trait is associated with each sex
reciprocal cross
the parental individuals used in an initial genetic cross
P generation
first generation of offspring from a genetic cross
F1 generation
second generation of offspring from a genetic cross produced by interbreeding F1 individual
F2 generation
one of 2 or more versions of a gene
alleles
the masking effect of one allele over another
dominance
mendel’s principle that the pairs of alleles that control a character segregate as gametes are formed with half the gametes carrying one allele, and the other half carrying the other allele
principle of segregation
an individual with 2 copies of same allele
homozygote
state of possessing 2 copies of the same allele
homozygous
an individual with 2 different alleles of a gene
heterozygote
state of possessing 2 different alleles of a gene
heterozygous
an F1 heterozygote produced from a genetic cross involves a single character
monohybrid
a genetic cross between 2 individuals that are each heterozygous for the same pair of alleles
monohybrid cross
the genetic constitution of an organism in terms of its genes and alleles
genotype
the observable or measurable characteristics of an organism that are produced by an interaction between the genotype and the environment
phenotype
the possibility that an outcome will occur if it is a mater of chance
probability
mathematical rule in which the final probability is found by multiplying individual probabilities
product rule
mathematical rule in which final probability by summing individual probabilities
sum rule
method for determining the genotype and phenotype of offspring and their expected proportions by combining gametes and their probabilities of occurrence in a matrix table
punnett square
a genetic cross between an individual with the dominant phenotype and a homozygous recessive individual
testcross
a zygote produced from a cross that involves 2 characters
dihybrid
a cross between 2 individuals that are heterozygous for 2 pairs of alleles
dihybrid cross
Mendel’s principle that the alleles of the genes that govern 2 characters assort independently during formation of gametes. mechanistically this is the case because any combination of chromosomes may be segregated to the spindle poles during meiosis I
independent assortment
Mendel’s principle that the alleles of the genes that govern 2 characters assort independently during formation of gametes
Principle of Independent Assortment
the principle that genes and their alleles are carried on the chromosomes
chromosome theory of inheritance
the particular site on a chromosome at which a gene is located
locus
condition in which the effects of recessive alleles can be detected to some extent in heterozygotes
incomplete dominance
condition in which alleles have approximately equal effects in individuals making the alleles equally detectable in heterozygotes
codominance
more than 2 different alleles of a gene
multiple alleles
interaction of genes with one or more alleles of a gene at one locus inhibiting or masking the effects of one or more alleles of a gene at a different locus
epistasis
inheritance in which several to many different genes contribute to the same character
polygenic inheritance
a character that displays a continuous distribution of the phenotype involved typically resulting from several to many contributing genes
quantitative traits
the individual genes that contribute to a quantitative trait
quantitative trait loci
condition in which single genes affect more than one character of an organism
pleitropy
theory suggesting that hereditary traits blend evenly in offspring through mixing of the blood of 2 parents
blending theory of inheritance
