Terminology Genes are present on sex chromosome (mostly on X chromosome with no corresponding gene on the Y chromosome) and expressed more often in one sex type than the other Genes present on the same chromosome and are inherited together Genes present on different chromosomes and they are inherited independently Where the inheritance of two traits is tracked Where the inheritance of one trait is tracked Where the gametes are placed on the two sides of a square to cross and determine the possible offsprings Refers to a cross made to determine the genotype of an individual that expresses a dominant phenotype Refers to when the two alleles are different - one dominant and one recessive allele Refers to when both the alleles are the same - two dominant or two recessive alleles Refers to the actual alleles present Refers to the expression of the alleles or the appearance of the trait It is expressed only when dominant allele is absent If present, it is expressend in the individual; it masks the expression of the recessive allele Where the same trait is expressed generation after generation Alternative forms of a gene

True-breeding crosses

Principles of inheritance

Test cross

Monohybrid cross

Dihybrid cross