Pedigrees, Sex-linked & Extranuclear Inheritance

These flashcards cover key concepts related to pedigrees, sex-linked traits, inheritance patterns, and other genetic principles mentioned in the lecture notes.

Pedigree

A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors.

Sex-linked traits

Traits that are associated with genes located on sex chromosomes, typically the X chromosome in mammals.

Autosomal inheritance

Inheritance of traits determined by genes located on autosomes (non-sex chromosomes).

Haplodiploid system

A sex-determination system in which males develop from unfertilized eggs and are haploid, while females develop from fertilized eggs and are diploid.

Extranuclear inheritance

Inheritance patterns involving genetic material outside the nucleus, such as that found in mitochondria and chloroplasts.

X-linked dominant

A mode of inheritance where a dominant gene is located on the X chromosome, affecting both males and females, but typically showing different expressions.

Environmental sex determination (ESD)

A system where environmental factors, such as temperature, influence the sex of an organism.

Genetic sex determination (GSD)

A system in which sex is determined by specific sex chromosomes.

Autosomes

Chromosomes that are not sex chromosomes; in humans, chromosomes 1 through 22 are autosomal.

Homogametic

Referring to the sex that has two of the same sex chromosomes (e.g., XX in females).

Heterogametic

Referring to the sex that has two different sex chromosomes (e.g., XY in males).

Punnett square

A diagram used to predict the outcome of a genetic cross by considering all possible combinations of gametes.

Monohybrid cross

A genetic cross involving a single trait, typically between two individuals heterozygous for that trait.

Phenotype

The observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Mitochondrial DNA (mtDNA)

Genetic material found in mitochondria, inherited maternally and involved in energy production.