Principles of Genetics – Introduction to Genetics, History, and Terminology (Video)

Vocabulary flashcards covering key concepts, terms, and theories from the Genetics lecture notes.

Genetics

The science of heredity and variation; term coined by Bateson in 1905, from the Greek 'gen' meaning to beget or produce.

Heredity

The passage of traits from parents to offspring.

Inheritance

The transmission of characters from generation to generation and the patterns by which this occurs.

Gene

A unit of heredity; a DNA segment that produces a functional product and is commonly associated with a trait.

DNA

Deoxyribonucleic acid; a polymer of nucleotides that stores genetic information; bases are A, T, C, G.

Nucleotide

The basic building block of DNA consisting of a sugar, phosphate group, and a nitrogenous base.

Chromosome

A DNA-protein structure that carries genes; located in the nucleus.

Homologous chromosomes

Chromosomes of the same size, shape, and gene position that pair during meiosis.

Alleles

Alternative forms of a gene at the same locus on homologous chromosomes.

Genotype

The genetic makeup of an individual (e.g., RR, Rr, rr).

Phenotype

The observable traits of an organism (e.g., tall vs. dwarf).

Homozygous

Having identical alleles for a trait (e.g., RR or rr).

Heterozygous

Having different alleles for a trait (e.g., Rr).

Gamete

A reproductive cell possessing a haploid set of chromosomes (n).

Zygote

Fertilized egg; a cell with a diploid set of chromosomes (2n).

Monohybrid cross

Cross involving a single gene (e.g., Rr); gametes R and r.

Dihybrid cross

Cross involving two genes (e.g., RrYy); four possible gametes.

Trihybrid cross

Cross involving three genes (e.g., TtRrYy); multiple gamete combinations.

Polyhybrid

A cross involving more than three heterozygous genes.

Selfing

Self-fertilization of a plant; the same plant provides both gametes.

Crossing

Mating between two different plants or individuals.

Reciprocal cross

Crosses in which the parental genders are swapped to test inheritance patterns.

Back cross

Cross F1 with one of the parental genotypes (often to introduce a dominant trait).

Test cross

Cross F1 with a recessive individual to reveal the genotype of the F1.

Dominant

Allele that is expressed in the phenotype when present in a heterozygote or homozygote.

Recessive

Allele that is expressed only when homozygous (needs two copies).

Complete dominance

One allele fully masks the effect of the other in the phenotype.

Partial dominance

An intermediate phenotype in the heterozygote (incomplete dominance).

Co-dominance

Both alleles are expressed simultaneously in the heterozygote.

Heterodominance

A condition where the F1 phenotype is more or less than either parent.

Mendel

Gregor Johann Mendel; founder of genetics; proposed particulate inheritance in 1866.

Germplasm theory

Weismann's idea that germ cells carry hereditary information and are immortal.

Pangenesis

Darwin's hypothesis that minute particles (pangenes) from body parts are transmitted to offspring.

Epigenesis

Theory that new structures arise during development from epigenetic processes; de novo formation.

Preformation theory

Idea that embryos develop from preformed miniature organisms (homunculus) in the sperm or egg.

Central dogma

DNA is transcribed into RNA, which is translated into proteins; flow of genetic information.

Transcription

Process of copying DNA sequence into RNA.

Translation

Process of converting RNA sequence into an amino acid sequence to form a protein.

Phenylketonuria (PKU)

Genetic disorder causing accumulation of phenylalanine; can be managed by diet to prevent damage.