Bio H 24-25 - Intro to Genetics

Genetic trait

Inherited characteristic of an organism.

Variable traits

Differ among individuals of the same species.

Invariant traits

Identical in all individuals of the species.

Biochemical traits

Traits often more difficult to observe.

Physical traits

Easily observable characteristics of an organism.

Behavioral traits

Behaviors influenced by genetic factors.

Gene

Basic unit of information in genetics.

Heterozygous

Genotype with two different alleles.

Mutation

Change in DNA sequence affecting traits.

Gregor Mendel

Father of modern genetics, studied pea plants.

Genetic cross

Breeding experiment to study inheritance patterns.

P Generation

Initial parental generation in a genetic cross.

Homozygous Dominant

Genotype with two dominant alleles (e.g., PP).

Homozygous Recessive

Genotype with two recessive alleles (e.g., pp).

Law of Segregation

Alleles separate during gamete formation.

Law of Independent Assortment

Genes segregate independently during gamete formation.

Recessive Phenotype

Trait that reappears in F2 generation.

Cross-Pollination

Fertilization between different plant varieties.

Hybrid Offspring

Offspring with mixed genetic traits (e.g., Pp).

Probability of Event

Chance that a specific outcome will occur.

Black-Coated Dogs

Example of a genetic cross with specific traits.

True-Breeding

Organisms that consistently pass down specific traits.

Crisscrossing Plants

Method used by Mendel to study inheritance.

Offspring Display

Phenotypes exhibited by the next generation.

Law of Dominance

Dominant traits are expressed over recessive traits.

Mendelian Traits

Traits controlled by a single gene.

Alleles

Different forms of a gene.

Heterozygote

Organism with two different alleles for a trait.

Independent Assortment

Genes segregate independently during gamete formation.

Incomplete Dominance

Neither allele fully expresses, blending occurs.

Codominance

Both alleles are fully expressed in phenotype.

Phenotype

Observable traits of an organism.

Genotype

Genetic makeup of an organism.

Punnett Square

Diagram predicting offspring genotypes.

Recessive Allele

Allele whose effect is masked by dominant.

Homologous Chromosomes

Chromosome pairs, one from each parent.

Fertilization

Fusion of sperm and egg cells.

Complex Traits

Traits influenced by multiple genes.

Chromosome Theory of Inheritance

Genes are located on chromosomes and inherited.

Punnett square

A diagram predicting offspring genotypes.

Polygenic traits

Traits controlled by multiple genes.

Siamese cat coat color

Color pattern influenced by temperature and genes.

Complex traits

Traits influenced by multiple genetic and environmental factors.

Lark and Ostrander

Researchers identifying genes related to dog traits.

Recessive allele

An allele that is masked by a dominant allele.

Dominant allele

An allele that masks the effect of a recessive allele.

Cross-breeding

Mating individuals to study genetic inheritance.

Homozygous

Having identical alleles for a gene.

F1 Generation

First filial generation from parental cross.

F2 Generation

Second filial generation from F1 cross.

Epistasis

Two genes are inherited independently, but the alleles of one gene affect the expression of another gene’s alleles.

Pleiotropy

Single gene affecting multiple traits.

Genetic Cross

Mating of two organisms to study inheritance.