Genetics - Patterns of Inheritance

Flashcards about Genetics - Patterns of Inheritance

Alleles

Different versions of the same gene that cause trait differences.

Chromosomes

Come in pairs; includes homologous chromosomes, autosomes, and sex chromosomes.

Homologous chromosomes

Matching pairs of chromosomes.

Autosomes

Non-sex chromosomes.

Sex chromosomes

Determine male or female.

Meiosis

Makes gametes (eggs/sperm) that have half the number of chromosomes (haploid).

Genotype

Genetic makeup (alleles you have).

Phenotype

Physical traits you see.

Homozygous

Two same alleles (e.g., AA or aa).

Heterozygous

Two different alleles (e.g., Aa).

Dominant Allele

Shows up if present.

Recessive Allele

Shows up only if no dominant allele.

Law of Segregation

Two alleles for a trait separate during meiosis and go into different gametes.

P generation

Parent plants/organisms.

F1 generation

First offspring.

F2 generation

Second offspring.

True breeding

Parents with same traits produce offspring with same traits.

Test cross

Cross an unknown genotype with a homozygous recessive to find out the unknown genotype.

Law of Independent Assortment

Alleles for different traits separate independently during meiosis.

Complete dominance

Dominant allele completely hides recessive.

Codominance

Both alleles show equally (e.g., blood type AB).

Incomplete dominance

Mix of both alleles (e.g., red + white = pink flowers).

Epistasis

One gene can block or mask another (example: mouse coat color).

Polygenic inheritance

Many genes add up to affect one trait (e.g., skin color).

Multifactor traits

Traits can be affected by both genes and environment.

Pedigrees (Family Trees)

Charts showing traits in families, used to track inheritance of traits or genetic disorders.

Linked Genes

Genes on the same chromosome can be inherited together.

Genetic Linkage

Genes on the same chromosome can be inherited together - called genetic linkage.

Linkage maps

Show gene locations based on how often crossing over occurs.

Sex Chromosomes (Humans)

XX = female, XY = male in humans.

X-linked traits

On the X chromosome.

X chromosome inactivation

In females, one X is randomly turned off (example: tortoiseshell cats).