DNADeoxyribonucleic acid (diːˈɒksᵻˌraɪboʊnjuːˌkliːᵻk,_-ˌkleɪ-; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids. Alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.
Genetic programmingIn artificial intelligence, genetic programming (GP) is a technique of evolving programs, starting from a population of unfit (usually random) programs, fit for a particular task by applying operations analogous to natural genetic processes to the population of programs. The operations are: selection of the fittest programs for reproduction (crossover), replication and/or mutation according to a predefined fitness measure, usually proficiency at the desired task.
DNA sequencingDNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery. Knowledge of DNA sequences has become indispensable for basic biological research, DNA Genographic Projects and in numerous applied fields such as medical diagnosis, biotechnology, forensic biology, virology and biological systematics.
Sense (molecular biology)In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context, sense may have slightly different meanings. For example, negative-sense strand of DNA is equivalent to the template strand, whereas the positive-sense strand is the non-template strand whose nucleotide sequence is equivalent to the sequence of the mRNA transcript.
Trisomy 18Trisomy 18, also known as Edwards syndrome, is a genetic disorder caused by the presence of a third copy of all or part of chromosome 18. Many parts of the body are affected. Babies are often born small and have heart defects. Other features include a small head, small jaw, clenched fists with overlapping fingers, and severe intellectual disability. Most cases of trisomy 18 occur due to problems during the formation of the reproductive cells or during early development. The chance of this condition occurring increases with the mother's age.
ChromosomeA chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation.
Chromosome 21Chromosome 21 is one of the 23 pairs of chromosomes in humans. Chromosome 21 is both the smallest human autosome and chromosome, with 45 million base pairs (the building material of DNA) representing about 1.5 percent of the total DNA in cells. Most people have two copies of chromosome 21, while those with three copies of chromosome 21 have Down syndrome, also called "trisomy 21". Researchers working on the Human Genome Project announced in May 2000 that they had determined the sequence of base pairs that make up this chromosome.
Homologous chromosomeA couple of homologous chromosomes, or homologs, are a set of one maternal and one paternal chromosome that pair up with each other inside a cell during fertilization. Homologs have the same genes in the same loci where they provide points along each chromosome which enable a pair of chromosomes to align correctly with each other before separating during meiosis. This is the basis for Mendelian inheritance which characterizes inheritance patterns of genetic material from an organism to its offspring parent developmental cell at the given time and area.
AneuploidyAneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes. A cell with any number of complete chromosome sets is called a euploid cell. An extra or missing chromosome is a common cause of some genetic disorders. Some cancer cells also have abnormal numbers of chromosomes. About 68% of human solid tumors are aneuploid.
Patau syndromePatau syndrome is a syndrome caused by a chromosomal abnormality, in which some or all of the cells of the body contain extra genetic material from chromosome 13. The extra genetic material disrupts normal development, causing multiple and complex organ defects. This can occur either because each cell contains a full extra copy of chromosome 13 (a disorder known as trisomy 13 or trisomy D or T13), or because each cell contains an extra partial copy of the chromosome, or because there are two different lines of cells—one healthy with the correct number of chromosomes 13 and one that contains an extra copy of the chromosome—mosaic Patau syndrome.
