inheritance

• what is an allele?

  a different form of the same gene
• genes come in pairs
• a dominant allele = always expressed if present in the genotype
• a recessive allele = only expressed if no dominant alleles present in the genotype
• a dominant allele written as a capital letter
• a reccessive allele writen lowercase
• what are the different genotypes?

  Homozygous dominant (GG)

  Homozygous reccessive (gg)

  heterozygous (Gg)
• individual with 2 dominant alleles = homozygous dominant
• individual with 2 recessive alleles = homozygous recessive
• individual with 1 recessive + 1 dominant = heterozygous
• homozygous = same
• heterozygous (don't define) = different
• what is a phenotype?

  the physical feature that is expressed.
• what is the difference between a genotype and a phenotype?

  a phenotype is the physical feature expressed whereas a genotype is how many dominant or recessive alleles the individual is composed of
• what do we call different versions of a gene?

  alleles
• the stronger gene = dominant gene
• the weaker gene = the recessive gene