topic 8 genetics

gregor mendel

the fasther of genetics, made science shift to the Discrete Packet (gene/allele) Model

laws of segregation and independent assortment

law of segregation

alleles segregate freely, offspring have equal chances of inheriting one singular factor

law of independent assortment

offspring can have any/all possible combinations, genes do not influence each other

monohybrid cross

fertilization between two true-breeding things that differ in only one characteristic

ex. P x p

dihybrid cross

fertilization between two true-breeding things that differ in two characteristics

ex. PPRR x pprr

linkage

crossing over during meiosis that disrupts independent assortment and the geno/pheno predictions from mendel

incomplete dominance

two contrasting alleles display an indeterminant phenotype (white flower x red flower = pink flower)

codominance

complete and simultaneous expression of BOTH alleles for the same characteristic (blood types A, B, O, AB)

polygenic inheritance

each law contributes some hormone or melanin w/ additive effects, produces a large variety (height, skin color)