Founder Effect: A phenomenon that is observed when a small subgroup of a larger POPULATION establishes itself as a separate and isolated entity. The subgroup's GENE POOL carries only a fraction of the genetic diversity of the parental population resulting in an increased frequency of certain diseases in the subgroup, especially those diseases known to be autosomal recessive.Haplotypes: The genetic constitution of individuals with respect to one member of a pair of allelic genes, or sets of genes that are closely linked and tend to be inherited together such as those of the MAJOR HISTOCOMPATIBILITY COMPLEX.Pedigree: The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.Jews: An ethnic group with historical ties to the land of ISRAEL and the religion of JUDAISM.Microsatellite Repeats: A variety of simple repeat sequences that are distributed throughout the GENOME. They are characterized by a short repeat unit of 2-8 basepairs that is repeated up to 100 times. They are also known as short tandem repeats (STRs).Africa, Northern: The geographical area of Africa comprising ALGERIA; EGYPT; LIBYA; MOROCCO; and TUNISIA. It includes also the vast deserts and oases of the Sahara. It is often referred to as North Africa, French-speaking Africa, or the Maghreb. (From Webster's New Geographical Dictionary, 1988, p856)Gypsies: Ethnic group originating in India and entering Europe in the 14th or 15th century.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Indians, Central American: Individual members of Central American ethnic groups with ancient historic ancestral origins in Asia. Mexican Indians are not included.Genetic Variation: Genotypic differences observed among individuals in a population.Genetics, Population: The discipline studying genetic composition of populations and effects of factors such as GENETIC SELECTION, population size, MUTATION, migration, and GENETIC DRIFT on the frequencies of various GENOTYPES and PHENOTYPES using a variety of GENETIC TECHNIQUES.National Socialism: The doctrines and policies of the Nazis or the National Social German Workers party, which ruled Germany under Adolf Hitler from 1933-1945. These doctrines and policies included racist nationalism, expansionism, and state control of the economy. (from Columbia Encyclopedia, 6th ed. and American Heritage College Dictionary, 3d ed.)DNA Mutational Analysis: Biochemical identification of mutational changes in a nucleotide sequence.Consanguinity: The magnitude of INBREEDING in humans.Gene Frequency: The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Genes, Recessive: Genes that influence the PHENOTYPE only in the homozygous state.Newfoundland and Labrador: Province of Canada consisting of the island of Newfoundland and an area of Labrador. Its capital is St. John's.Keratoderma, Palmoplantar: Group of mostly hereditary disorders characterized by thickening of the palms and soles as a result of excessive keratin formation leading to hypertrophy of the stratum corneum (hyperkeratosis).Linkage Disequilibrium: Nonrandom association of linked genes. This is the tendency of the alleles of two separate but already linked loci to be found together more frequently than would be expected by chance alone.Dermatitis, Exfoliative: The widespread involvement of the skin by a scaly, erythematous dermatitis occurring either as a secondary or reactive process to an underlying cutaneous disorder (e.g., atopic dermatitis, psoriasis, etc.), or as a primary or idiopathic disease. It is often associated with the loss of hair and nails, hyperkeratosis of the palms and soles, and pruritus. (From Dorland, 27th ed)Indians, South American: Individual members of South American ethnic groups with historic ancestral origins in Asia.Genetic Structures: The biological objects that contain genetic information and that are involved in transmitting genetically encoded traits from one organism to another.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Australasia: Australia, New Zealand and neighboring islands in the South Pacific Ocean. (Random House Unabridged Dictionary, 2d ed.)Genetic Drift: The fluctuation of the ALLELE FREQUENCY from one generation to the next.Nontherapeutic Human Experimentation: Human experimentation that is not intended to benefit the subjects on whom it is performed. Phase I drug studies (CLINICAL TRIALS, PHASE I AS TOPIC) and research involving healthy volunteers are examples of nontherapeutic human experimentation.Homozygote: An individual in which both alleles at a given locus are identical.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.DNA, Mitochondrial: Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.Gene Flow: The change in gene frequency in a population due to migration of gametes or individuals (ANIMAL MIGRATION) across population barriers. In contrast, in GENETIC DRIFT the cause of gene frequency changes are not a result of population or gamete movement.Heterozygote: An individual having different alleles at one or more loci regarding a specific character.Arabs: Members of a Semitic people inhabiting the Arabian peninsula or other countries of the Middle East and North Africa. The term may be used with reference to ancient, medieval, or modern ethnic or cultural groups. (From Random House Unabridged Dictionary, 2d ed)Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.Chromosomes, Human, Y: The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Genetic Markers: A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.Genetic Linkage: The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.Genetic Testing: Detection of a MUTATION; GENOTYPE; KARYOTYPE; or specific ALLELES associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing.Tunisia: A country in northern Africa between ALGERIA and LIBYA. Its capital is Tunis.Genetic Heterogeneity: The presence of apparently similar characters for which the genetic evidence indicates that different genes or different genetic mechanisms are involved in different pedigrees. In clinical settings genetic heterogeneity refers to the presence of a variety of genetic defects which cause the same disease, often due to mutations at different loci on the same gene, a finding common to many human diseases including ALZHEIMER DISEASE; CYSTIC FIBROSIS; LIPOPROTEIN LIPASE DEFICIENCY, FAMILIAL; and POLYCYSTIC KIDNEY DISEASES. (Rieger, et al., Glossary of Genetics: Classical and Molecular, 5th ed; Segen, Dictionary of Modern Medicine, 1992)Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Penetrance: The percent frequency with which a dominant or homozygous recessive gene or gene combination manifests itself in the phenotype of the carriers. (From Glossary of Genetics, 5th ed)Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Polymorphism, Genetic: The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.France: A country in western Europe bordered by the Atlantic Ocean, the English Channel, the Mediterranean Sea, and the countries of Belgium, Germany, Italy, Spain, Switzerland, the principalities of Andorra and Monaco, and by the duchy of Luxembourg. Its capital is Paris.Exons: The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.Chromosomes, Human, Pair 2: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.Mediterranean Region: The MEDITERRANEAN SEA, the MEDITERRANEAN ISLANDS, and the countries bordering on the sea collectively.Introduced Species: Non-native organisms brought into a region, habitat, or ECOSYSTEM by human activity.Genes, BRCA1: A tumor suppressor gene (GENES, TUMOR SUPPRESSOR) located on human CHROMOSOME 17 at locus 17q21. Mutations of this gene are associated with the formation of HEREDITARY BREAST AND OVARIAN CANCER SYNDROME. It encodes a large nuclear protein that is a component of DNA repair pathways.Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.EuropeMutation, Missense: A mutation in which a codon is mutated to one directing the incorporation of a different amino acid. This substitution may result in an inactive or unstable product. (From A Dictionary of Genetics, King & Stansfield, 5th ed)Genetic Speciation: The splitting of an ancestral species into daughter species that coexist in time (King, Dictionary of Genetics, 6th ed). Causal factors may include geographic isolation, HABITAT geometry, migration, REPRODUCTIVE ISOLATION, random GENETIC DRIFT and MUTATION.Point Mutation: A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.Germ-Line Mutation: Any detectable and heritable alteration in the lineage of germ cells. Mutations in these cells (i.e., "generative" cells ancestral to the gametes) are transmitted to progeny while those in somatic cells are not.BRCA2 Protein: A large, nuclear protein, encoded by the BRCA2 gene (GENE, BRCA2). Mutations in this gene predispose humans to breast and ovarian cancer. The BRCA2 protein is an essential component of DNA repair pathways, suppressing the formation of gross chromosomal rearrangements. (from Genes Dev. 2000;14(11):1400-6)Polymorphism, Single-Stranded Conformational: Variation in a population's DNA sequence that is detected by determining alterations in the conformation of denatured DNA fragments. Denatured DNA fragments are allowed to renature under conditions that prevent the formation of double-stranded DNA and allow secondary structure to form in single stranded fragments. These fragments are then run through polyacrylamide gels to detect variations in the secondary structure that is manifested as an alteration in migration through the gels.Family Health: The health status of the family as a unit including the impact of the health of one member of the family on the family as a unit and on individual family members; also, the impact of family organization or disorganization on the health status of its members.Spinocerebellar Degenerations: A heterogenous group of degenerative syndromes marked by progressive cerebellar dysfunction either in isolation or combined with other neurologic manifestations. Sporadic and inherited subtypes occur. Inheritance patterns include autosomal dominant, autosomal recessive, and X-linked.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Age of Onset: The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.FinlandItalyFrameshift Mutation: A type of mutation in which a number of NUCLEOTIDES deleted from or inserted into a protein coding sequence is not divisible by three, thereby causing an alteration in the READING FRAMES of the entire coding sequence downstream of the mutation. These mutations may be induced by certain types of MUTAGENS or may occur spontaneously.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Emigration and Immigration: The process of leaving one's country to establish residence in a foreign country.Spain: Parliamentary democracy located between France on the northeast and Portugual on the west and bordered by the Atlantic Ocean and the Mediterranean Sea.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.Population Density: Number of individuals in a population relative to space.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.AfricaPolymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Polymorphism, Restriction Fragment Length: Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.Codon, Nonsense: An amino acid-specifying codon that has been converted to a stop codon (CODON, TERMINATOR) by mutation. Its occurance is abnormal causing premature termination of protein translation and results in production of truncated and non-functional proteins. A nonsense mutation is one that converts an amino acid-specific codon to a stop codon.IsraelQuebec: A province of eastern Canada. Its capital is Quebec. The region belonged to France from 1627 to 1763 when it was lost to the British. The name is from the Algonquian quilibek meaning the place where waters narrow, referring to the gradually narrowing channel of the St. Lawrence or to the narrows of the river at Cape Diamond. (From Webster's New Geographical Dictionary, 1988, p993 & Room, Brewer's Dictionary of Names, 1992, p440)Genetic Predisposition to Disease: A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.North AmericaSequence Deletion: Deletion of sequences of nucleic acids from the genetic material of an individual.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Genes, Dominant: Genes that influence the PHENOTYPE both in the homozygous and the heterozygous state.Family: A social group consisting of parents or parent substitutes and children.Syndrome: A characteristic symptom complex.Chromosomes, Human, Pair 11: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.