Basics of Inheritance Flashcards
Homozygote
An individual organism possessing two of the same alleles at a locus
Addition rule of probability
the probability of a single, mutually exclusive event can be determined by adding the probabilities of the two or more different ways in which this single event could take place
allows for predicting the likelihood of a single event that can happen in two or more ways
Genotype
set of alleles possessed by an individual organism
Principle of Segregation (Mendel’s First Law)
each individual diploid organism has a pair of alleles (a copy) for a particular trait, copies of genes separate/segregate so that each gamete receives only one allele; used when thinking about one trait
Segregation results from
the separation of homologous chromosomes in meiosis
Independent assortment results from
the independent separation of chromosomes in anaphase 1 of meiosis
Multiplication rule of probability
the probability of two independent events occurring together is the product of their probabilities of occurring independently; allows for predicting the probability of two or more independent events occurring together
P
Parental generation
F1
first filial generation
F2
second filial generation
Gene
basic unit of heredity; an inherited factor (encoded in the DNA) that helps determine a characteristic
Allele
one of two or more alternative forms of a gene
Locus
specific place on a chromosome occupied by an allele
Heterozygote
an individual organism possessing two different alleles at a locus
Phenotype/Trait
the appearance or manifestation of a characteristic
Characteristic/Character
an attribute or feature possessed by an organism
Principle of Independent Assortment (Mendel’s Second Law)
the alleles of two (or more) different genes get sorted into gametes independently of one another; the allele a gamete receives for one gene does not influence the allele received for another gene; used when thinking about two or more different traits
ex: seed shape will sort independently of seed color
True Breeding
all offspring resulting from parental crosses will have the same phenotype; no matter how many times a cross is performed, identical phenotypes will occur each time; refers to organisms that are homozygous for genes (both alleles are the same, so PP instead of Pp)
Punnett Square
a square diagram that is used to predict the genotypes (unique DNA patterns) of a particular cross or breeding experiment; phenotypes (physical expression of genotypes) can also be predicted
Probability
A number that describes how likely it is that an event will occur; 1 = event is certain to happen, 0 = event cannot possibly happen, and all other events have a probability between 0 and 1
How many potential outcomes are there for two genes?
16
