Ch08 Inheritance, Genes, Chromosomes, Mendel Flashcards
observable physical feature
character or trait
(though NOT necessarily “visible”
crossing individuals for 1 trait
monohybrid cross
technically, this means the parents have contrasting traits
different forms of a gene
allele
ah-LEEL
form of a gene that hides/masks/covers the presence of another form of that gene
dominant
if the dominant form of the gene is present, it will be expressed
form of a gene that gets masked/hidden/covered up by the presence of another form of that gene
recessive
recessive genes will only be expressed in the absence of a dominant form of that gene
having two alleles that are the SAME
homozygous
sometimes called “pure”
having two alleles that are DIFFERENT
heterozygous
sometimes called “hybrid”
physical appearance of an organism
phenotype
phenotypes are the expression of the genes - though not necessarily “visible”
genetic make up of an organism
genotype
“type-o-gene”
when an individual produces gametes, the 2 copies of a gene separate, so that each gamete receives only one copy
law of segregation
used to determine whether an individual showing the dominant trait is “homozygous” or “heterozygous”
test cross (cross the individual with the dominant trait with a recessive individual)
cross between individuals that are double heterozygotes
TtSs
dihybrid cross
alleles of different genes assort independently of one another during gamete formation
- genes are not (necessarily) inherited together
law of independent assortment
be aware of the exceptions to this rule
how do you determine the probability of two or more independent events occurring together?
you multiply their individual probabilities
product rule
how do you determine the probability of an event that can occur in two or more different ways?
add their individual probabilities
addition rule
a family tree that follows the inheritance of a particular trait
pedigree
inheritance characterized by an intermediate phenotype
incomplete dominance
inheritance in which two alleles of a genotype are both expressed
codominance
expression of one gene is affected by another gene
epistasis
phenotypes are determined by multiple genes
quantitative traits
polygenic traits
particular site of a gene on a chromosome
gene locus
loci
when gene loci are on the same chromosome and therefore often inherited together
linked
gene shuffling, crossing over, and random fertilization all contribute to increased variation in offspring. This mixing of genetic information is
recombination
chromosomes that determine the sex of the individual
sex chromsomes
chromosomes that do not influence the sex of the individual
autosomes
inheritance of a gene that is carried on a sex chromosome
sex-linked
typically “X” linked
female genotype
XX
male genotype
XY
For sex-linked inheritance - females that have a recessive allele on one X chromosome (affected) and one dominant allele (unaffected) on her other X chromosome
carrier
transmission of plasmids (DNA) from one bacterium to another
conjugation
