Inheritance

• Genotype

  the genetic constitution of an organism (the alleles it has for a gene)
• phenotype

  the expression of the genes and its interaction with the environment
• homozygous

  a pair of homologous chromosomes carrying the same alleles for a single gene
• heterozygous

  a pair of homologous chromosomes carrying two different alleles for a single gene
• recessive allele

  an allele only expressed if no dominant allele is present
• dominant allele


  an allele that will always be expressed in the phenotype
• codominant

  both alleles are equally dominant and expressed in the phenotype
• multiple alleles

  more than two alleles for a single gene
• sex-linkage

  a gene whose locus is on the X chromosome
• autosomal linkage

  genes that are located on the same chromosome (not the sex chromosome)
• epistasis

  when one gene modifies or masks the expression of a different gene at a different locus
• monohybrid

  genetic inheritance cross of a characteristic determined by one gene
• dihybrid

  genetic inheritance cross for a characteristic determined by two genes