Applications and Modifications in Genetics

Incomplete Dominance

Discovery after Mendel that indicated that genes were not always completely dominant.

Codominance

The existence of two dominant traits that would both show up in the offspring expressed in a heterozygous condition.

46 chromosomes

The number of chromosomes a cell has. 23 from the father, 23 from the mother.

Autosomes

Contains 22 pairs of chromosomes, particularly 44 non-sex chromosomes and 2 sex chromosomes.

Karyotype

Contains 22 pairs of homologous chromosomes decreasing in size.

Sex Chromosomes

Genetic material that determines the sex of an organism at fertilization. The man’s sperm determines the sex of the children.

XX Chromosome

Female sex chromosome.

XY Chromosome

Male sex chromosome.

Thomas Hunt Morgan

Scientist who studied genetic variations in drosophila (fruit flies) and discovered sex-linked traits.

Sex-linked Traits

These are genetic results related to the sex that were crossed.

Colorblindness

A sex-linked trait that makes the organism see colors differently than most people.

Hemophilia

A sex-linked trait that is related to the blood’s inability to clot properly. Known as “Bleeder’s Disease”.

Mutation

Change in the DNA or genetic material of the cell that may cause it and all cells derived from it to differ in appearance or behavior from normal cells.

Somatic Mutation

Mutation that occurs in blood cells and does not get passed on to the offspring.

Germ Mutation

Mutation that occurs in reproductive cells and gets passed on to the offspring.

Karl Landsteiner

Austrian physician who discovered blood types in 1900.

Blood Types

Determined by the difference in blood chemistry of the red blood cells and certain chemicals in the plasma.

Antibody

Proteins in plasma that react with specific antigens that enter the blood.

Antigen

Substances that simulate the production of antibodies.

Type O

Universal blood donor.

Type AB

Universal blood receiver.