Mendelian Genetics

Flashcards covering key concepts from Mendelian Genetics.

Heredity

The passing on of characteristics/traits from parents to offspring.

Pea Plants

Mendel used pea plants as they are good model organisms, can self-pollinate or be cross-pollinated, and have a short reproductive cycle with many offspring.

Alleles

Different versions of the same gene.

True-breeding

A line of plants that only produces plants with a specific trait when self-pollinated.

Hybrids

The offspring of two dissimilar organisms.

Genotype

The combination of alleles an individual has, represented with 2 letters for alleles on homologous chromosomes.

Phenotype

The expression of genes, such as physical appearance or metabolic characteristics.

Punnett Square

A statistical tool used to predict phenotypic and genotypic outcomes of a genetic cross.

Dominance vs. Recessiveness

One allele is dominant (expressed), and the other is recessive (only expressed if both alleles are recessive).

Law of Segregation

Each gamete receives one allele per gene due to the separation of homologous chromosomes during meiosis.

Autosomal Traits

Traits with genes located on autosomes that follow Mendelian inheritance.

Bi-parental Inheritance

Organisms inherit 2 alleles—1 from each parent; the alleles may be the same or different.

Law of Independent Assortment

Alleles of different genes assort independently during gamete formation.

Carrier

A heterozygous individual who carries one recessive allele but does not express the disorder; can pass it to offspring.

Dihybrid Cross

A cross performed if both parents are heterozygous for two traits.

Recessive Disorder

Genetic disorders that require two copies of the recessive allele to express the disorder.

Non-disjunction

The process that violates the law of segregation.

Segregation of Alleles

The separation of alleles during gamete formation through meiosis.

Autosomal Dominant Representation

Capital letter for dominant allele.

Autosomal Recessive Representation

Lowercase letter for recessive allele.

PKU

Phenylketonuria, caused by a mutation in the PAH gene on chromosome 12, leading to a toxic buildup of phenylalanine.