Genetic Variance in Humans

Meiosis - the process to create gametes (egg and sperm cells) that have 1/2 the number of chromosomes as regular cells.

Crossing Over - the formation of recombinant chromosomes during prophase I, allowing exchange of genetic material between homologous chromosome pairs resulting in non-identical sister chromatids.

Random Segregation - the random division of chromosomes into 4 separate gametes.

Independent Assortment - alleles/genetic traits are inherited independently of each other (higher chance of variation).

Crossing Over

DNA Replication Error - errors in replication can cause minor to significant changes in a genetic sequence.

Insertion - adding or "inserting" a codon or sequence to a DNA strand.

Deletion - losing or "deleting" a codon or sequence from a DNA strand.

Subsitution - replacing a codon or sequence with the same number of codons within a DNA strand.

Subtopic

Environmental Influence/Mutagens - outside agents that alters the genetic code.

Physical - radiation and particles damage or alter DNA structure or replication.

X-Ray

Heat

Chemical - chemicals that directly interact with DNA causing breakage or altering structure. Chemicals that can indirectly damage/alter DNA by enabling the creation of mutagenic compounds.

Base Analog

Intercalating Agent

Alkylating Agent

Deaminating Agent

Metals

Biological - altering DNA structure or replication via living organism, disrupting check and repair systems.

Bacteria

Virus

Mutagens

Examples

Mutagens

Cancer, Cystic Fibrosis, Crohn's Disease

DNA Replication Error

Sickle-Cell Anemia, Seasonal Flu Virus (new strains)

Meiosis

Eye color, Skin color, Hair color