Glossary of Terms for The DNA Diet Site

Carolyn’s DNA Diet Glossary

Allele   Alternative form of a genetic locus; a single allele for each locus is inherited separately from each parent (e.g., at a locus for eye color the allele might result in blue or brown eyes).

Autosomal Dominant   
inheritance refers to genetic conditions that occur when a mutation is present in one copy of a given gene (i.e., the person is heterozygous).

Autosomal recessive inheritance
refers to genetic conditions that occur only when mutations are present in both copies of a given gene (i.e.  an individual is homozygous for a mutation, or carries two different version of the same gene)

Autosome  
A chromosome not involved in sex determination. The diploid human genome consists of 46 chromosomes, 22 pairs of autosomes and 1 pair of sex chromosomes (the X and Y chromosomes).

Carbohydrate
is an organic compound derived from sugar that is the main ingredient of many types of food.  Carbohydrates contain carbon, hydrogen and oxygen and may form long chains of various types of sugars including glucose, fructose, galactose, mannose, etc.  Carbohydrates provide 4 calories per gram as energy.

Copy Number Variants (CNV)
are large-scale structural changes in DNA that vary from individual to individual. These include insertions, deletions, duplications and complex multi-site variants that range from kilobases to megabases in size. CNV can influence gene expression, phenotypic variation and alter gene dosage, and in certain instances may be associated with developmental disorders, cause disease or confer susceptibility to complex disease traits.

Detoxification  the process by which a substance that isn’t useful as energy or building new cell structures is removed from the body.   Often used to describe removal of alcohol or drugs but it may be expanded to any substance that isn’t useful and may be harmful in excess.

DNA (Deoxyribonucleic acid) is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA). The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences. DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.
An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.

DNA Polymorphisms include SNP’s and CNV and describe the variability of DNA or difference in DNA sequence among individuals. Genetic variations occurring in more than 1% of a population would be considered useful polymorphisms for genetic linkage analysis.

Fat (see Lipid) is a white, oily substance in the body that stores energy, protects the body and acts as an insulator.  It is also a substance found in foods providing 9 calories per gram which is more than twice as energy dense as carbohydrates or protein.

Gene
  The fundamental physical and functional unit of heredity. A gene is an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional product (i.e., a protein or RNA molecule).  Genes code for amino acids which when formed combine into peptides and proteins.

Genetic Linkage Analysis is
a gene-hunting technique that traces patterns of heredity in large, high-risk families, in an attempt to locate a disease-causing gene mutation by identifying traits that are co-inherited with it.

Genetic profile
  A collection of information about a person's genes.

Genetic markers 
 Alleles of genes, or DNA polymorphisms, used as experimental probes to keep track of an individual, a tissue, a cell, a nucleus, a chromosome, or a gene.  Stated another way, any character that acts as a signpost or signal of the presence or location of a gene or heredity characteristic in an individual in a population. There are 4 chromosome changes that do occur from generation to generation, and these are known as markers

Glycemic Index (GI)
Glycemic is a term describing glucose levels in the blood (David Jenkins, 1981)

Glycemic Load (GL)
is a ranking system for a combination of foods based on their glycemic index and portion size.  The formula is GL = GI x amount of carbohydrate/100 (University of Sydney, 2006)

Lipid
is a compound that is insoluble in water and is comprised mainly of carbon and hydrogen.  Lipids include fats which are solid at room temperature and oils which are liquid at room temperature.

Omega-3
is a polyunsaturated fatty acid found in fish oils, seeds, whole grains and some tree nuts.  An intake of 2-4 grams daily is recommended for healthy cardiovascular and nervous system functioning.

Protein
is a compound that is an essential part of living cells and is one of the elements of food necessary to keep the human body working properly.  Protein is composed of carbon, hydrogen, oxygen and nitrogen.  It is the nitrogen fraction that separates a protein from a carbohydrate or fat.  Proteins are made up of amino acids and peptides (small groups of amino acids linked together). 

SNP (single nucleotide polymorphism) is a small genetic change, or variation, that can occur within a person's DNA sequence. The genetic code is specified by the four nucleotide "letters" A (adenine), C (cytosine), T (thymine), and G (guanine). SNP variation occurs when a single nucleotide, such as an A, replaces one of the other three nucleotide letters—C, G, or T.

Sulfur amino acids
are cysteine, methionine and taurine.  These are amino acids that include the mineral sulfur (chemical symbol S) and have a capacity to form a bond between the sulfur residues thus providing a particular shape to the protein.  Examples include hemoglobin, immunoglobulin and insulin.  Sulfur containing proteins include glutathione (L-glutamyl-L-cysteinylglycine) which forms an important part of the detoxification process.  Glutathione is also known as GSH and is oxidized to glutathione disulfide GSSG which is two molecules connected by a sulfur bond.  The ratio between reduced and oxidized glutathione is an estimate of toxicity at the cellular level.

Please see  http://ghr.nlm.nih.gov/Resources/genome for more on The Human Genome Project