Addition- A type of genetic mutation where a piece is added where it should not be.
Adenine- A nitrogenous base of DNA, which pairs up with thymine.
Albinism- A condition caused by a genetic mutation in which the skin lacks the ability to produce pigment.
Amniocentesis- A technique of obtaining genetic material from a fetus in the uterus, via a long needle. Those samples can then be karyotyped to check for chromosomal aberrations.
Anaphase- The stage of cellular division when the chromosomes begin to divide and separate towards the opposing centrioles.
Antigen- A foreign substance that enter the body and triggers a response against it, or a chemical produced by certain types of blood.
Aster- The radiating spindle threads from the centrioles.
Autosome- A cell that is not a sex cell.
Blood type- One of four characteristically different types of blood: A, B, AB and O. The types are a result of antigens A and B being either present or absent in the blood.
Cell plate- The part of a cell wall that develops between dividing plant cells.
Centriole- The organelle found in the cytoplasm that is connected to the spindle during cellular division.
Centromere- The region on a chromosome where the spindle attaches, and where double chromatids are held together.
Centrosomes- The body that contains the centriole.
Chromatin- The genetic material within the nucleus that eventually takes the shape of chromosomes at the beginning of mitosis.
Chromosome- A rod-like structure made of genetic material.
Chronic Villus sampling- A technique of obtaining genetic material from a fetus in the uterus, via suction. Usually considered more dangerous that amniocentesis, it can be used early in the pregnancy.
Cloning- The artificial production of organisms that have identical genetic material.
Codominance- A type of partial dominance in which both phenotypes are displayed; e.g. the roan coat of the shorthorn cattle, since there are red and white hairs.
Codon- A combination of three nucleotides on m-RNA that directs the order of the amino acids to produce proteins.
Colorblind- A genetic disorder characterized by an inability to distinguish between colors.
Cooley’s Anemia- See Thalassemia.
Crossing over- The counterpoint to gene linkage; when genetic material is swapped between homologous chromosomes in synapsis.
Cystic Fibrosis- A genetic disorder caused by a recessive allele on the 7th chromosome, when an over-secretion of mucus damages the lung.
Cytosine- A nitrogenous base of DNA, which pairs up with guanine.
Deletion- A type of genetic mutation where a piece is taken away when it should not be.
Deoxyribose- A sugar and a part of DNA.
Diploid- A cell with two sets of chromosomes.
DNA- Deoxyribonucleic acid. A molecule that contains the genetic information of a living cell. It is composed of a sugar called deoxyribose, a phosphate, and a nitrogenous base.
Double Helix The model of DNA, or a ladder twisted upon itself.
Down syndrome- A chromosomal aberration resulting from nondisjunciton, when the cells have an extra 21st chromosome.
Drosophila melanogaster- The scientific name for the fruit fly used in many genetic experiments.
Egg- The female gamete.
Eugenics- The science of improving the human race by applying our knowledge of genetics.
Gametes- A mature reproductive cell; a sperm for males and eggs for females.
Gametogenesis- The process by which gametes, are produced, be it spermatogenesis of oogenesis.
Gene linkage- The idea that genes on the same chromosome are inherited together.
Genetic screening- A technique for the detection of genetic disorders by checking for certain telltale chemicals in bodily fluids.
Guanine- A nitrogenous base of DNA, which pairs up with cytosine.
Haploid- See Monoploid.
Hemoglobin- The protein in blood that contains iron, carries oxygen, and gives blood its red color.
Hemophilia- A genetic disorder characterized by an inability of blood to clot.
Homologous pairs- The pair of corresponding chromosomes, or one set from each parent.
Huntington’s Disease- A genetic disease caused by a dominant allele which progressively breaks down brain cells.
Incomplete Dominance- A type of partial dominance in which a middle state is found in the heterozygous between the two phenotypes; e.g. the pink flower of the snapdragon.
Indent- The division of a cell membrane after mitosis or meiosis,
Intermediate Inheritance- See Partial Dominance.
Interphase- The first stage of mitosis where genetic replication takes place.
Inversion- A type of genetic mutation where the genetic material becomes reversed.
Karyotype- A picture of chromosomes, arranged in their homologous pairs and in numerical order. A karyotype can be used to detect chromosomal aberrations.
Law of Independent Assortment- The law that states that genes located on nonhomologous chromosomes are independently from one another.
Lou Gehrig’s Disease- (Amyotrophic lateral sclerosis) A genetic disease which causes muscular and nervous degeneration until death.
Meiosis- The cellular division where one diploid cell becomes four monoploid cells.
Metaphase- The stage in cellular division when the chromosomes are located in the middle of the cell.
Mitosis- A division of a cell into two exact copies of the same cell.
Monoploid- A cell with only one set of chromosomes.
Multiple Alleles- A trait that has more than one allele, such as blood type.
Mutation- An alteration in the genetic material of an organism.
Nitrogenous base- A part of DNA and RNA, which makes up the rungs of the ladder; cytosine, guanine, thymine, adenine or uracil.
Nondisjunction- A type of chromosomal mutation in which an entire chromosome or more does not divide properly during gametogenesis.
Oogenesis- The development of one egg cell and three polar bodies from one primary sex cell in the ovaries.
Ovaries- The place in the female body where oogenesis occurs.
Partial Dominance- When the dominance of a trait does not follow the laws of dominance and recession. Incomplete dominance and Codominance are examples of partial dominance. Also known as intermediate inheritance.
Phenylaline- An amino acid that builds up in the brain when not converted into tyrosine, causing PKU.
Phenylketonuria- (PKU) A genetic disorder which causes weak-mindedness, due to a buildup of the phenylaline in the brain.
Phosphate group- A part of DNA, making up the sides of the ladder.
Plasmid- The rings of DNA in bacteria like E. coli that are used in the process of recombinant DNA.
Polar bodies- The three rejected monoploid cells of Oogenesis.
Polyploidy- A genetic mutation in which there is are whole extra sets of chromosomes. This type of mutation can sometimes be beneficial in farming, because polyploidy plants often yield larger fruits and flowers.
Prophase- The stage in mitotic or meiotic division where the genetic material becomes chromosomes.
Punnet Square- A written diagram that shows the inheritance of a particular gene in all possible combinations.
Recombinant DNA- A DNA molecule artificially produced in the laboratory by joining other pieces together.
Reduction-Division- The division during meiosis where the diploid primary sex cell becomes two monoploid cells.
Rh factor- A blood factor that can cause blood poisoning between mothers and their yet to be born babies.
RNA- Ribonucleic acid, functions in the production of proteins as messenger, transfer, or ribosomal RNA. Consists of a ribose sugar and a nitrogenous base.
Sickle-cell anemia- A genetic disorder that causes red blood cells to become sickle-shaped, from a problem in the hemoglobin. The malformed cells cause pain and swelling before disintegrating.
Sperm- The male gamete.
Spermatogenesis- The development of four sperm cells from one male primary sex cell in the testes.
Spindle- Fine threads of cytoplasm that connect chromosomes to centrioles.
Synapsis- The pairing of homologous chromosomes during meiosis when crossing over occurs.
Tay-Sachs- A genetic disease that causes death to very young children, due to a lack of hexosaminidase-A. A buildup of fatty matter in the brain causes the loss of life functions.
Telophase- The final phase of cellular division, when the cytoplasm and chromosomes have all divided.
Test cross- In order to determine whether a phenotypically dominant trait is homozygous or heterozygous, a test cross is performed by crossing the organism with one that has the recessive trait homozygously.
Testes- The place in the male body where spermatogenesis occurs.
Thalassemia- A genetic disorder that occurs as the body can not produce enough red blood cells with the right amount of hemoglobin.
The Human Genome project- (HGP) An effort to fully map out the human genetic code, or genome, in order to further our capabilities in genetic therapy.
Translocation- A type of genetic mutation where a gene is transferred to a nonhomologous chromosome.
Vestigial wings- Wings that have developed to much less than full size due to a mutation.
X chromosome- The chromosome that makes a female a female, when accompanied by another X. Sex linked traits occur on the X chromosome.
Y chromosome- The chromosome that makes a male a male, when accompanied by another X.