gene segregation and interaction

law of segregation

when an organism makes gametes, each gamete receives just one copy selected randomly; either parental or recombinant

law of independent assortment

genes do not influence e/o w regards to sorting of alleles into gametes; every possible combination of alleles for every gene is equally likely to occur

law of independent assortment

heredity doesn’t influence heredity of another; gene a will not affectr gene b; modifier gene

complete dominance

This results in only the dominant trait being expressed in the phenotype.

incomplete dominance

mixture or blending of trait in the offspring, where neither allele is completely dominant over the other.

overdominance

offspring has stronger phenotype than the parents

co-dominance

mixture of both traits are fully expressed in the phenotype, resulting in a distinct appearance of both traits. b&w

lethal genes

Genes that can cause death in the organism when present in certain combinations, often leading to reduced viability in offspring.

recessive lethal

homo recessive dies; lethal when in homo recessive condition

dominant lethal

single dominant dies; lethal effects occur when a dominant allele is present in a homo or hetero condition

recessive epistasis

complete dominance at both gene pairs but homo recessive gene is epistatic or masks the effect of the other gene

dominant epistasis

complete dominance at both genes but dominant gene is epistatic to the other or mask the effect of the other

epistasis

mask the effect of one gene

genotype

genetic code; genetic constitution that an indiv inherits

phenotype

physical manifestation; appearance, morphology, physiology, and behavior of an organism

law of dominance

dominant allele manifests; selfing

heterosis

superiority of f1 hybrid over its parents

pleiotropic gene

can be labeled as 2 types; one gene has multiple phenotypic effects

allelic interactions

only one gene controls the traits; single gene pair interact with eo

non-allelic interaction

two genes are controlling one trait resulting to modified f2 phenotypic ratios of dihybrid cross

duplicate genes

duplicate dominant epistasis ; complete dominance at both gene pairs but either gene when dominant is epistatic to the other

complementary genes

duplicate recessive epistasis ; homo recessive is epistatic to the effects of the dominant allele of the other gene

hymozygous

genotype of parental plants (p gen) from pure breeding lines of varieties

first filial generation

f1 means

Gregor mendel

proposed law of segregation and law of independent assortment

1:2:1:2:4:2:1:2:1

genotypic ratio of f2 in dihybrid cross

9:3:3:1

phenotypic ratio of f2 in dihybrid cross

multiple allele

occurs when more than two alleles exist in a gene

9:3:4

phenotypic ratio of recessive epistasis

12:3:1 or 13:3

phenotypic ratio of dominant epistasis

9:7

phenotypic ratio of complementary genes

15:1

phenotypic ratio when a dominant allele at either gene pair hides the effect of the ovoid

cis form

two dominants are on the same chromosome and their recessive counterparts are on the other chromosome

trans form

one dominant and one recessive on one chromosome and their respective recessive and dominant alleles on the other chromosome

expressivity

degree to which a particular phenotypic effect is exhibited by the indiv

chi square test

stat test used in gene segregation; usually applied to numerical freq, not to percentages or ratios derived from freq

degrees of freedom

number of classes upon which x2 value is based must be considered in evaluating its significance

single pair of alleles or a single gene

Mendel’s law of segregation applies to behavior of a

two or more genes/pairs of alleles

law of independent assortment applies when ___ are considered simultaneously

dihybrid cross

Mendel based his second law on the results of his

first division segregation

means that the separation of diff parent alleles occurs in first meiotic division

second division segregation

is the result of a crossover between two chromatids of the homologues in the region between the genes and the centromere so that the two diff alleles remain tgt in the meiosis I but eparate in meiosis II