Autosomal Recessive Inheritance

1. Autosomal Recessive Inheritance • Characteristics of autosomal recessive inheritance: • no difference in expression between males and females • matings between affected individuals produce 100% affected offspring • Affected genotype (filled in shape) must be “dd” • Unaffected genotypes (empty shapes) can be either “DD” or “Dd”

2. Autosomal Dominant Inheritance • Characteristics of autosomal dominant inheritance: • no difference in expression between males and females • no unaffected heterozygous individuals • does not skip generations • Affected genotypes (filled in shapes) can be either “Dd” or “DD” • Unaffected genotype (empty shape) must be “dd”

3. Sex-linked (X-linked) recessive inheritance • Characteristics of sex-linked (X-linked) recessive inheritance: • most affected individuals will be male • affected females must have an affected father and either a heterozygous or affected mother • affected females will have 100% affected sons • tends to skip generations • Affected genotypes (filled in shapes) must be “XdXd ”or “XdY” • Unaffected genotypes (empty shapes) can be “XDXD ”, “XDXd ”, or “XDY”

4. Sex-linked (X-linked) Dominant Inheritance • Characteristics of sex-linked (X-linked) dominant inheritance: • affected males must have affected mothers • affected females must have one affected parent • affected males will have 100% affected daughters • affected females are expected to produce half normal, half affected offspring • Affected genotypes (filled in shapes) can be “XDXD ”, “XDXd ”, or “XDY” • Unaffected genotypes (empty shapes) must be “XdXd ”or “XdY”