Comprehensive Study Guide on Mendelian Genetics, Hereditary Laws, and Pedigree Analysis

Comprehensive vocabulary flashcards covering Mendel's experiments, laws of inheritance, alleles, genotypes, phenotypes, crosses, and probability based on the lecture notes.

Genetics

The study of biological inheritance patterns and variation in organisms.

Trait

A characteristic that is inherited, such as eye color or hair color.

Gregor Mendel

An Austrian monk known as the father of genetics who studied inheritance in pea plants during the 1800s.

Purebred

Organisms or plants that consistently produce offspring with the same traits, such as when self-pollinated.

Law of Segregation

Mendel's first law stating that organisms inherit two copies of each gene (one from each parent) and that these copies separate during gamete formation, leaving each gamete with only one copy.

Gene

A unit of inheritance passed down from parents; specifically, a section of DNA containing instructions for making a protein.

Locus

The specific location of a gene on a chromosome.

Allele

A different version of a gene.

Homozygous

Having two identical alleles for a gene, such as RR or rr.

Heterozygous

Having two different alleles for a gene, such as Rr.

Dominant Allele

An allele that is expressed when at least one dominant copy is present, represented by a capital letter.

Recessive Allele

An allele that is expressed only when two recessive copies are present, represented by a lowercase letter.

Genotype

The genetic combination of alleles an organism possesses (e.g., homozygous dominant, heterozygous, or homozygous recessive).

Phenotype

The physical or observable appearance of a trait, such as round or wrinkled peas.

Genome

All of an organism's genetic material.

Monohybrid Cross

A cross that examines the inheritance of one specific trait.

Dihybrid Cross

A cross that examines the inheritance of two different traits.

Law of Independent Assortment

Mendel's second law stating that alleles of different genes separate independently during gamete formation (meiosis).

Probability

The likelihood or chance that an event or particular outcome will occur, predicting the average likelihood rather than the exact result.

Cross

The mating of two organisms.

Testcross

A breeding cross between an organism with an unknown genotype and a homozygous recessive organism to determine the unknown genotype.

Pedigree

A diagram similar to a family tree that shows information about an inherited trait passed across generations.

Circle (Pedigree Symbol)

The shape used in a pedigree to represent females.

Square (Pedigree Symbol)

The shape used in a pedigree to represent males.

Roman Numerals (in a Pedigree)

Symbols used in a pedigree to represent different generations.

Marriage Line

A horizontal line that connects two parents in a pedigree.

Shaded Shapes (in a Pedigree)

Shapes in a pedigree that indicate individuals who possess or express the specific trait being tracked.

Dominant Alleles

Alleles that express dominant traits in typical Mendelian inheritance whenever they are present.

Recessive Alleles

Alleles that are only expressed when the dominant allele is not present.

Autosome

A chromosome that is not a sex chromosome, making up the first $44$ chromosomes ($22$ pairs) in human body cells.

Sex Chromosomes

The last $2$ chromosomes ($1$ pair) in human body cells, designated as XX for females and XY for males.

Carrier

An individual with a heterozygous genotype who carries a recessive allele and can pass it on, but does not display the recessive trait due to having a dominant allele.

Sex-Linked Trait

A trait associated with genes located on sex chromosomes, such as color-blindness and some male patterns of baldness.

Half-Shaded Shape (in a Pedigree)

A symbol used on some pedigrees to explicitly identify individuals who are carriers of the trait.