Unit 2 - Final Review Flashcards
Gregor Mendel
father of genetics. Studied pea plants.
Gene Pool
all the genes in a given population
Allele
alternate forms of a gene controlling a characteristic.
Found in the same position (locus) of homologous chromosomes
Pure
homozygous dominant or homozygous recessive
Heterozygous
genotype with 1 dominant and 1 recessive. Hybrid.
Genotype
alleles that make up a trait
Phenotype
observable characteristics of an organism.
Monohybrid cross
cross involving a single traits
Dihybrid cross
cross involving two traits
Generations naming
P1 = parents
F1 = first generation (filial)
F2 = 2nd generation
Mendels ratios (2 x heterozygous)
making two heterozygotes = 3:1 phenotype ratio, dominant: recessive
Mendel’s Laws of Heredity
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment
Law of Dominance
In heterozygotes, the dominant alleles will mask the recessive allele; the dominant allele will be expressed exclusively.
Law of Segregation
during the formation of gametes, the two alleles responsible for a trait will separate. Offspring will receive one allele from each parent, which are recombined during fertilization = offspring genotype.
Law of Independent Assortment
alleles are randomly distributed to gametes. the allele that a gamete receives for one gene does not affect the allele that it receives for a different gene.
Genotypic ratios
homozygous dominant: heterozygous: homozygous recessive
Phenotypic ratios
dominant: recessive
test cross
performed between a homozygous individual and an unknown individual
Autosomal dominant
Both males and females are equally affected.
Unaffected parents cannot produce an affected child
x-linked recessive
Mostly males affected
No transmission of trait from father to son