Human+Genetics+DF

this type of allele (e)
 * Genotype** – specific genes for a particular trait written with symbols //EE or Ee or ee//
 * Alleles**: alternate forms of a specific gene at the same position (locus) on a gene (e.g. allele for unattached earlobes and attached lobes); alleles occur in pairs //E or e//
 * Dominant allele**: will be expressed and will mask a recessive gene (E)
 * Recessive allele**: allele that is only expressed when a gene has two of
 * Homozygous dominant genotype**: 2 dominant alleles (EE)
 * Homozygous recessive genotype**: 2 recessive alleles (ee)
 * Heterozygous genotype**: one dominant allele and one recessive allele (Ee)

One gene Two genes
 * Gametes**:
 * Parent EE gametes E
 * Parent ee gametes e
 * Parent **Ee** gametes **E or e**
 * Parent FFee gametes Fe
 * Parent Ffee gametes Fe or fe
 * Parent FfEe gametes FE or Fe or fE or fe

Questions using Punnett Squares
 * Ee x Ee**: Chances kid will be attached? 1 in 4 or 25%
 * Phenotypic ratio**: 3 unattached: 1 attached
 * Genotypic ratio**: 1 EE : 2 Ee : 1 ee

This pedigree is for an autosomal dominant trait. How can you tell?

These pedigrees are for autosomal recessive traits. How can you tell?