8.1 Genetics Flashcards
genotype
allele combination
homozygous
both same allele
heterozygous
two different alleles
phenotype
visible trait
genotypic ratio
ratio of offspring’s genotypes
phenotypic ratio
ratio of offspring’s phentypes
dominant
only need one allele to cause phenotype
recessive
need both alleles to cause phenotype
co-dominance
both alleles visible in phenotype
ratios: homozygous dominant x homozygous dominant
geno- 4/4 homozygous dominant
pheno- 4/4 dominant
ratios: homozygous dominant x homozygous recessive
geno- 4/4 heterozygous
pheno- 4/4 dominant
ratios: homozygous dominant x heterozygous
geno- 2/4 homozygous dominant:2/4 heterozygous
pheno- 4/4 dominant
ratios: heterozygous x heterozygous
geno- 1/4 homozygous dominant:2/4 heterozygous:1/4 homozygous recessive
pheno- 3/4 dominant:1/4 recessive
ratios: heterozygous x homozygous recessive
geno- 2/4 heterozygous:2/4 homozygous recessive
pheno- 2/4 dominant:2/4 recessive
ratios: homozygous recessive x homozygous recessive
geno- 4/4 homozygous recessive
pheno- 4/4 recessive
ratios: co-dominance
geno: same as dominant/recessive
pheno: heterozygous has its own phenotype, so pheno ratio is the same as geno ratio
ratios: multiple alleles
geno: same as dominant/recessive
pheno: same as dominant/recessive just with more possible phenotypes
test crosses
predict parent’s genotype using offspring’s phenotype ratio
cross both dominant genotypes with recessive genotype and compare phenotype ratios to actual offspring
Mendelian crosses: generations
P = parent (removed male parts to control which plants reproduced)
F1 = filial 1 (first group of offspring)
F2 = filial 2 (second group of offspring)
Mendelian crosses: P generation
two homozygous individuals with different phenotypes (one dominant, one recessive)
