Autosomal = Inherited on the body chromosomes #1-44.Sex-Linked = Inherited on the Sex Chromosomes #45 & 46. (XX or Xy)
Pedigree SymbolsPedigree Symbols
Autosomal Dominant Traits1. Almost all individuals will be heterozygous. (Hh)
2. Every affected individual has an affected biological parent. There is no skipping of generations.
3. Males and females have an equally likely chance of inheriting the mutant allele and being affected. The recurrence risk of each child of an affected parent is 1/2.
4. Normal siblings of affected individuals do not transmit the trait to their offspring.
5. There are never carriers (half-shaded symbols).
Autosomal DominantAutosomal Dominant
Autosomal Dominant DisordersDisease Symptoms
Symptoms may include involuntary movements and loss of motor control. In addition, personality changes may occur, with loss of memory and decreased mental capacity.
Achondroplasia (dwarfism)Achondroplastic dwarfs have short stature, with an average adult height of 131 cm (4’3”)
PolydactlyDisorder of more than 5 fingers or toes per appendage.
a legal dwarf
1. Traits will often skip a generation.2. Parents may not have the trait, but can pass it
on to offspring. (e.g. Het)3. Males and Females are equally affected.4. Both parents can be carriers. (half-shade)
Examples: Examples: *Cystic fibrosis
Males and females are equally likely to be Males and females are equally likely to be affected.affected.
TThe recurrence risk to the unborn sibling he recurrence risk to the unborn sibling of an affected individual is 1/4.of an affected individual is 1/4.
The trait is characteristically found in The trait is characteristically found in siblings, not parents of affected or the siblings, not parents of affected or the offspring of affected.offspring of affected.
Parents of affected children may be Parents of affected children may be related. The rarer the trait in the general related. The rarer the trait in the general population, the more likely a population, the more likely a consanguineous mating is involved.consanguineous mating is involved.
Albinism InheritanceWhich Type of Inheritance is this?
Circled symbols show Heterozygous Individual (Aa)What’s gross about this pedigree?
Jamaican Albino “Yellow Mon”
1. Passed on from the (X) Sex Chromosome.2. Fathers pass trait on to daughters.3. Mother’s pass trait on to daughters or sons.4. Usually skips a generation.5. Males more likely affected than females.6. Female carriers possible, not males.