Genetics - Patterns Of Heredity

Patterns of Heredity

 How

do you find out the chances of passing a trait to your children?  Answer  Pedigree A

family history that shows how a trait is inherited over several generations.  Particularly helpful in finding carriers for genetic disorders.

 Carriers  They

are Heterozygous

don’t show symptoms of the disorder they are carrying.  Can pass trait to offspring.  Ex. Albinism (Disorder that does not produce melanin; no skin color)

 Remember

Autosomes?  Inherited traits can be either Autosomal or Sex-linked.  Autosomal Traits – appear in both males and females.

 Sex-linked

traits only appear on the Xchromosome of an individual. ** Males only have 1 chromosome; if they have the recessive allele, they will display the trait. ** Females have 2 chromosomes; they will only display the trait if they have both recessive alleles.

Color-Blindness

 Traits

can be Autosomal Dominant or Autosomal Recessive.  If Dominant, the child will have a parent with the trait  If Recessive…then one, both, or none of the parents will exhibit the trait.

Genetic Disorders  Genetic

disorders are caused by mutations, which are caused by damaged or faulty proteins.  Many disorders are caused by recessive alleles in heterozygous individuals.

Sickle Cell Anemia A

condition caused by a mutated allele that produces a defective form of the protein hemoglobin (in red blood cells).  Cannot easily transport Oxygen through the body.

Sickle Cell Anemia Pedigree

Hemophilia  Sex-linked

disorder that impairs blood’s ability to form clots.  If a male receives the recessive allele, he will have Hemophilia.