Chapter 10 Flashcards
particulate hypothesis of inheritance
parents pass on separate and distinct factors (genes) that are responsible for inherited traits
mendels methods
cross fertilization=sperm from the pollen of one flower fertilizes the eggs in the flower of a different plant
mendel’s principle of segregation
P=parent generation
F1=second generation
F2=third generation
Mendel’s 4 hypothesis
1) there are alternate forms of genes (alleles)
2) homozygous: 2 same alleles
heterozygous: 2 different alleles
3) if only one allele in a heterozygous person affects the trait, it is dominant, the other allele is recessive
4) the two alleles for a trait is separate during the formation of gametes, so each gamete carries only one allele for each trait
probability
there are many different possibilities for the gametes genes
genotype
genetic makeup or combination of alleles (Pp)
phenotype
observation trait (purple flowers)
mendel’s principle of independent assortment
in various dihybrid combinations the ratio for the F2 generation will be 9:3:3:1 peas
intermediate inheritance
when neither allele is dominant (use superscript letters= C^BC^W) chickens
multiple alleles
O=ii A=I^A I^A or I^A i B=I^B I^B or I^B i AB=I^A I^B type O=recessive type AB=codominant *blood types*
polygenic inheritance
when two or more genes affect a single character: height, skin color
environmental conditions
- nutrition influences height
- exercise affects build
- sunlight darkens skin
- wind affects tree leaves
chromosome theory of inheritance
genes are located on chromosomes and it is chromosomes that undergo segregation and independent assortment during meiosis
genetic linkage
the tendency for the alleles on one chromosome to be inherited together. the farther apart the genes are the more likely they will be separated during crossing over
sex-linked genes
any gene that is located on a sex chromosome (usually on the X)
ex=hemophilia and color blindness
