Autosomal Inheritance

Autosomal Dominant Examples

-Achondroplasia (dwarfism) -Brachydactyly (malformed hands with short fingers) -Huntington's Disease (fatal into later years, hereditary) -Neurofibromatosis (bumps on skin)

Autosomal Recessive Examples

-Albinism -Cystic fibrosis -Sickle cell anemia -Tay-Sachs disease

Hallmark Characteristics of Auto-Recessive

-Both parents have to have the mutant allele to pass on trait -There are carriers/ half shading -It can skip generations -Unaffected parents can have affected children (via carriers-1:4 chance of having kid with disorder) -All children of 2 affected parents are affected -Affected male and female equally

Mendelian Disorders

-Sickle cell anemia -Huntington's Disease -Tay-Sachs Disease -Cystic Fibrosis

Hallmark Characteristics of Auto-Dom

-affected trait in every generation -males and females can be affected equally -no carriers -only one parent has to have the disorder to pass it on to child -Affected parents can have unaffected children (only with Aa)

Inherited Human Traits

1. Widows peak 2. Earlobe attachment 3. Tongue rolling 4. Cleft chin 5. Dimples 6. Freckles 7. Allergies 8. Naturally curly hair

Autosomal recessive

Autosomal recessive is one of the several ways that a trait, disorder, or disease can be passed down through families. An autosomal recessive disorder means two copies of an abnormal gene must be present in order for the disease or trait to develop.

Incomplete penetrance

Inheritance: This pattern occurs when a dominant phenotype is not expressed even though an individual carries a dominant allele. Molecular: Even though a dominant gene may be present, the protein encoded by the gene may not exert its effects. This can be due to environmental influences or to other genes that may encode proteins that counteract the effects of the dominant allele.

Codominance

Inheritance: This pattern occurs when the heterozygote expresses both alleles simultaneously without forming an intermediate phenotype. For example, in blood typing, an individual carrying the A and B alleles has an AB blood type. Molecular: The codominant alleles encode proteins that function slightly differently from each other, and the function of each protein in the heterozygote affects the phenotype uniquely.I

Incomplete dominance

Inheritance: This pattern occurs when the heterozygote has a phenotype that is intermediate between either corresponding homozygote. For example, a cross between homozygous red-flowered and homozygous white-flowered parents produces heterozygous offspring with pink flowers. Molecular: 50% of a functional protein is not sufficient to produce the same trait as the homozygote making 100%.

Overdominance

Inheritance: This pattern occurs when the heterozygote has a trait that is more beneficial than either homozygote. Molecular: Three common ways that heterozygotes gain benefits: (1) Their cells may have increased resistance to infection by microorganisms; (2) they may produce more forms of protein dimers, with enhanced function; or (3) they may produce proteins that function under a wider range of conditions.

Autosomal dominant

Inheriting a disease, condition, or trait depends on the type of chromosome affected (nonsex or sex chromosome). It also depends on whether the trait is dominant or recessive. A single abnormal gene on one of the first 22 nonsex (autosomal) chromosomes from either parent can cause an autosomal disorder.

Hemizygous

Males have a single X chromosome.

Autosomal Inheritance

a pattern of inheritance in which the transmission of traits depends on the presence or absence of certain alleles on the autosomes.

Wild-type alleles

an allele that is fairly prevalent in a natural population, generally greater than 1% of the population. For polymorphic genes, there is more than one wild-type allele.

Simple Mendelian Inheritance

an inheritance pattern involving a simple, dominant/recessive relationship that produces observed ratios in the offspring that readily obey Mendel's laws.

Mendelian Inheritance

describes inheritance patterns that obey two laws: the law of segregation and the law of independent assortment. Until now, we have mainly considered traits that are affected by a single gene that is found in two different alleles.

X-linked recessive

this pattern involves the inheritance of genes that are located on the X chromosome. Males have a single copy of X-linked genes, whereas females have two copies. AT MOLECULAR LEVEL: If a pair of X-linked alleles shows a simple dominant/recessive relationship, the dominant allele encodes a functional protein, and 50% of the protein is sufficient to produce the dominant trait (in the heterozygous female).

Genetic polymorphism

when two or more alleles occur in population; each allele is found at a frequency of 1% or higher.