HG 4 Pedigrees and Inheritance Patterns

Flashcards for reviewing lecture notes on Pedigrees and Inheritance Patterns.

Pedigrees

Graphical representations of a family history that shows how traits or characteristics are passed down from generation to generation.

Pedigree Symbols

Standardized figures used internationally to overcome language barriers in pedigrees.

Horizontal Line (in a pedigree)

Indicates partners in a pedigree.

Vertical Line (in a pedigree)

Connects mating to offspring in a pedigree.

Bracket (in a pedigree)

Indicates all children from a mating in a pedigree.

Proband

The individual around whom the family tree is drawn, often indicated by an arrow.

Consanguineous Mating

A mating between related individuals, signified by a double mating line.

Abortions or stillbirths

Represented by a smaller symbol in a pedigree.

Child adopted into a family

Shown in closed brackets [ ] in a pedigree.

Sex-linked Traits

Traits caused by genes on the sex chromosomes.

X-linked traits

Disorders caused by genes on the X chromosome.

Y-linked traits

Disorders caused by genes on the Y chromosome.

Dystrophin

A protein found outside muscle fibers that protects them during contraction and relaxation.

Swyer Syndrome

The sex-determining region on the Y chromosome doesn't work properly, leading to genetic males with a uterus and fallopian tubes, but non-functional ovaries, causing infertility.

Sex Determination

The sex of the offspring is determined by the sperm.

Mitochondrial Inheritance

Mitochondria are only passed on from mother to child.

Campodactyly

A condition causing permanently bent little fingers and is inherited in an autosomal dominant manner.

Variable Expressivity

Expresses the variability in phenotype given a particular genotype.

Incomplete Penetrance

When a genotype does not always produce the expected phenotype.

Autosomal Recessive Trait

Requires two copies of the recessive allele for an individual to express the trait or disease.

Carriers

Individuals who are heterozygous (one dominant allele, one recessive) are half-shaded in pedigrees.

Autosomal Recessive Inheritance

A pattern of inheritance in which two copies of an abnormal gene must be present in order for the disease or trait to develop.

CFTR

Regulates the ow of chloride ions and adjusts the amount of water in cellular secretions.

Hemoglobin

An oxygen transport molecule in red blood cells (RBCs).

Autosomal Dominant Inheritance

Heterozygous and homozygous individuals are affected.

Marfan Syndrome

A disease of connective tissues resulting from mutations in the Fibrillin-1 gene.