Topics 1-2, 3, and 5

Genetics

Study of heredity and hereditary variation.

Heredity

Transmission of traits across generations.

Traits

Characteristics passed from parents to offspring.

Genes

Segments of DNA coding for heredity.

Chromosomes

Structures carrying genes from parents to offspring.

Asexual Reproduction

Single individual produces genetically identical offspring.

Sexual Reproduction

Two parents create genetically varied offspring.

Homologous Chromosomes

Pairs carrying same genetic information from parents.

Karyotypes

Ordered display of chromosome pairs by size.

Somatic Cells

Diploid body cells with two chromosome sets.

Gametic Cells

Haploid sex cells with one chromosome set.

Autosomes

Non-sex chromosomes; humans have 22 pairs.

Sex Chromosomes

Determine sex; X and Y chromosomes.

Life Cycle

Stages from conception to reproduction of organism.

Fertilization

Sperm and egg fuse to form zygote.

Meiosis

Process creating haploid gametes in diploid organisms.

Meiosis I

First division producing two haploid cells.

Meiosis II

Second division resulting in four genetically unique cells.

Crossing Over

Exchange of DNA between homologous chromosomes.

Independent Assortment

Random orientation of chromosomes during metaphase.

Random Fertilization

Any sperm can fertilize any egg.

Genetic Variation

Diversity in gene combinations among offspring.

Telophase

Final stage of cell division with nuclei reappearing.

Common Ancestry

DNA and RNA transmit genetic information across species.

Genetic Code

Universal code shared by all living organisms.

Gregor Mendel

Austrian monk known as the father of genetics.

Pea Plants

Mendel used them for controlled genetic experiments.

True Breeding

Organisms produce identical offspring through self-pollination.

P Generation

True-breeding parental generation in Mendel's experiments.

F1 Generation

First filial generation, hybrid offspring of P generation.

F2 Generation

Second filial generation, offspring of F1 hybrids.

Punnett Squares

Diagrams predicting allele combinations in offspring.

Homozygous

Identical alleles for a character in an organism.

Heterozygous

Two different alleles for a gene in an organism.

Genotype

The genetic makeup of an organism's alleles.

Phenotype

Observable traits determined by an organism's genotype.

Testcross

Determines if a dominant trait is homozygous or heterozygous.

Law of Segregation

Alleles separate during gamete formation.

Law of Independent Assortment

Genes for different traits segregate independently.

Monohybrid Crosses

Crosses examining one trait's inheritance.

Dihybrid Crosses

Crosses examining two traits' inheritance.

3:1 Ratio

Observed in F2 generation of monohybrid crosses.

9:3:3:1 Ratio

Phenotypic ratio from dihybrid crosses.

Somatic Cells

Diploid cells containing two chromosome copies.

Alleles

Alternative gene versions influencing traits.

Dominant Trait

Trait expressed in heterozygous condition.

Recessive Trait

Trait masked in heterozygous condition.

Gametes

Reproductive cells carrying one allele per trait.

Pedigrees

Family trees visualizing inheritance patterns.

Probability Rules

Laws governing genetic trait inheritance likelihood.

Multiplication Rule

Calculates probability of independent events occurring together.

Addition Rule

Calculates probability of mutually exclusive events occurring.

X-linked Traits

Traits associated with genes on the X chromosome.

Non-Mendelian Genetics

Traits that do not follow Mendel's laws.

Degrees of Dominance

Variation in dominance among alleles.

Incomplete Dominance

Neither allele is fully dominant; mixed phenotype.

Codominance

Both alleles expressed; distinct phenotypes visible.

Multiple Alleles

Genes with more than two allele forms.

Phenotypic Ratio

Proportion of different phenotypes in offspring.

Sex Chromosomes

Chromosomes determining an individual's sex.

Adjacent Genes

Genes close together segregate as a unit.

Non-Nuclear Inheritance

Inheritance from organelles like mitochondria.

F1 Generation

First filial generation from parental cross.

Human Blood Group

Example of codominance and multiple alleles.

Alleles

Different forms of a gene.

Black Mouse Cross

BB x bb results in gray offspring.

Cattle Color Genetics

RR, WW, RW explain red, white, roan.

Roan Cattle

RW genotype shows both red and white.

Type A Blood Genotype

Possible genotypes: IAIA or IAi.

Type B Blood Genotype

Possible genotypes: IBIB or IBi.

Phenotype

Observable traits resulting from genotype.

Multiple Genes Influence

Two or more genes determine phenotypes.

Mitochondrial DNA

DNA inherited maternally, affecting traits.

Chloroplast DNA

DNA from chloroplasts, involved in inheritance.

Epistasis

Gene interaction affecting phenotypic expression of another gene.

Polygenic inheritance

Multiple genes influence a single phenotype.

Sex-linked gene

Gene located on X or Y chromosome.

Y-linked genes

Genes specifically found on the Y chromosome.

X-linked genes

Genes located on the X chromosome.

Inheritance of X-linked genes

Fathers pass X-linked alleles to daughters only.

X-linked recessive trait

Females express trait only if homozygous.

Hemizygous

Males with one X chromosome for X-linked traits.

X-linked disorders

Conditions caused by mutations in X-linked genes.

Duchenne muscular dystrophy

Progressive muscle weakening disorder.

Hemophilia

Blood clotting disorder due to X-linked genes.

Color blindness

Inability to perceive colors correctly.

X-inactivation

Process where one X chromosome is inactivated in females.

Thomas Hunt Morgan

Scientist who studied sex-linked inheritance in fruit flies.

Normal allele (N)

Allele representing normal phenotype.

Affected allele (n)

Allele representing affected phenotype.

Inactive X chromosome

Condensed into Barr body in females.

Barr body

Inactive X chromosome regulating gene dosage.

Genetic recombination

New gene combinations from parental genes.

Parental types

Offspring with parental phenotype.

Recombinants

Offspring with different phenotypes than parents.

Independent assortment

Random distribution of chromosomes during meiosis.

Crossing over

Exchange of chromosome segments between chromatids.

Linked genes

Genes inherited together due to proximity.

Recombination frequency

Probability of gene separation during crossing over.

Linkage map

Genetic map based on recombination frequencies.