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Malecot's Method Of Coancestry
Malecot's coancestry coefficient, f, refers to an indirect measure of genetic similarity of two individuals which was initially devised by the French mathematician Gustave Malécot. f is defined as the probability that any two alleles, sampled at random (one from each individual), are identical copies of an ancestral allele. In species with well-known lineages (such as domesticated crops), f can be calculated by examining detailed pedigree records. Modernly, f can be estimated using genetic marker data. Evolution of inbreeding coefficient in finite size populations In a finite size population, after some generations, all individuals will have a common ancestor : f \rightarrow 1 . Consider a non-sexual population of fixed size N, and call f_i the inbreeding coefficient of generation i. Here, f means the probability that two individuals picked at random will have a common ancestor. At each generation, each individual produces a large number k \gg 1 of descendants, from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Measurement
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared to a basic reference quantity of the same kind. The scope and application of measurement are dependent on the context and discipline. In natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International Vocabulary of Metrology (VIM) published by the International Bureau of Weights and Measures (BIPM). However, in other fields such as statistics as well as the social and behavioural sciences, measurements can have multiple levels, which would include nominal, ordinal, interval and ratio scales. Measurement is a cornerstone of trade, science, technology and quantitative research in many disciplines. Historically, many measurement syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlantic, North Atlantic, the French West Indies, and List of islands of France, many islands in Oceania and the Indian Ocean, giving it Exclusive economic zone of France, one of the largest discontiguous exclusive economic zones in the world. Metropolitan France shares borders with Belgium and Luxembourg to the north; Germany to the northeast; Switzerland to the east; Italy and Monaco to the southeast; Andorra and Spain to the south; and a maritime border with the United Kingdom to the northwest. Its metropolitan area extends from the Rhine to the Atlantic Ocean and from the Mediterranean Sea to the English Channel and the North Sea. Its Regions of France, eighteen integral regions—five of which are overseas—span a combined area of and hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustave Malécot
Gustave Malécot (28 December 1911 – November 1998) was a French mathematician whose work on heredity had a strong influence on population genetics. Biography Malécot grew up in L'Horme, a small village near St. Étienne in the Loire département, the son of a mining engineer. In 1935, Malécot obtained a degree in mathematics from the École Normale Supérieure, Paris. He then went on to do a PhD under George Darmois and completed that in 1939. His work focused on R.A. Fisher's 1918 article ''The Correlation Between Relatives on the Supposition of Mendelian Inheritance''. Between 1940 and 1942, with France under Nazi German occupation, Malécot taught mathematics at the Lyceé de Saint-Étienne. In 1942 he was appointed maître de conférence (lecturer) Université de Montpellier. In 1945 he joined the Université de Lyon, becoming professor of applied mathematics Applied mathematics is the application of mathematics, mathematical methods by different fields ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alleles
An allele is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. Alleles can differ at a single position through single nucleotide polymorphisms (SNP), but they can also have insertions and deletions of up to several thousand base pairs. Most alleles observed result in little or no change in the function or amount of the gene product(s) they code or regulate for. However, sometimes different alleles can result in different observable phenotypic traits, such as different pigmentation. A notable example of this is Gregor Mendel's discovery that the white and purple flower colors in pea plants were the result of a single gene with two alleles. Nearly all multicellular organisms have two sets of chromosomes at some point in their biological life cycle; that is, they are diploid. For a given locus, if the two chromosomes contain the same allele, they, and the organism, are homozygous with respect to that allele. If the alleles are differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sample (statistics)
In this statistics, quality assurance, and survey methodology, sampling is the selection of a subset or a statistical sample (termed sample for short) of individuals from within a population (statistics), statistical population to estimate characteristics of the whole population. The subset is meant to reflect the whole population, and statisticians attempt to collect samples that are representative of the population. Sampling has lower costs and faster data collection compared to recording data from the entire population (in many cases, collecting the whole population is impossible, like getting sizes of all stars in the universe), and thus, it can provide insights in cases where it is infeasible to measure an entire population. Each observation measures one or more properties (such as weight, location, colour or mass) of independent objects or individuals. In survey sampling, weights can be applied to the data to adjust for the sample design, particularly in stratified samplin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Marker
A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can be observed. A genetic marker may be a short DNA sequence, such as a sequence surrounding a single base-pair change ( single nucleotide polymorphism, SNP), or a long one, like minisatellites. Background For many years, gene mapping was limited to identifying organisms by traditional phenotypes markers. This included genes that encoded easily observable characteristics, such as blood types or seed shapes. The insufficient number of these types of characteristics in several organisms limited the possible mapping efforts. This prompted the development of gene markers, which could identify genetic characteristics that are not readily observable in organisms (such as protein variation). Types Some commonly used types of genetic markers ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population
Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and plants, and has specific uses within such fields as ecology and genetics. Etymology The word ''population'' is derived from the Late Latin ''populatio'' (a people, a multitude), which itself is derived from the Latin word ''populus'' (a people). Use of the term Social sciences In sociology and population geography, population refers to a group of human beings with some predefined feature in common, such as location, Race (human categorization), race, ethnicity, nationality, or religion. Ecology In ecology, a population is a group of organisms of the same species which inhabit the same geographical area and are capable of Sexual reproduction, interbreeding. The area of a sexual population is the area where interbreeding is possi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Ancestor
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth. Common descent is an effect of speciation, in which multiple species derive from a single ancestral population. The more recent the ancestral population two species have in common, the more closely they are related. The most recent common ancestor of all currently living organisms is the last universal ancestor, which lived about 3.9 billion years ago. The two earliest pieces of evidence for life on Earth are graphite found to be biogenic in 3.7 billion-year-old metasedimentary rocks discovered in western Greenland and microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. All currently living organisms on Earth sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recurrence Relation
In mathematics, a recurrence relation is an equation according to which the nth term of a sequence of numbers is equal to some combination of the previous terms. Often, only k previous terms of the sequence appear in the equation, for a parameter k that is independent of n; this number k is called the ''order'' of the relation. If the values of the first k numbers in the sequence have been given, the rest of the sequence can be calculated by repeatedly applying the equation. In ''linear recurrences'', the th term is equated to a linear function of the k previous terms. A famous example is the recurrence for the Fibonacci numbers, F_n=F_+F_ where the order k is two and the linear function merely adds the two previous terms. This example is a linear recurrence with constant coefficients, because the coefficients of the linear function (1 and 1) are constants that do not depend on n. For these recurrences, one can express the general term of the sequence as a closed-form expression o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gametes
A gamete ( ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. The name gamete was introduced by the German cytologist Eduard Strasburger in 1878. Gametes of both mating individuals can be the same size and shape, a condition known as isogamy. By contrast, in the majority of species, the gametes are of different sizes, a condition known as anisogamy or heterogamy that applies to humans and other mammals. The human ovum has approximately 100,000 times the volume of a single human sperm cell. The type of gamete an organism produces determines its sex and sets the basis for the sexual roles and sexual selection. In humans and other species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete called an ovum, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coefficient Of Relationship
The coefficient of relationship is a measure of the degree of consanguinity (or biological relationship) between two individuals. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of the coefficient of inbreeding of 1921. The measure is most commonly used in genetics and genealogy. A coefficient of inbreeding can be calculated for an individual, and is typically one-half the coefficient of relationship between the parents. In general, the higher the level of inbreeding the closer the coefficient of relationship between the parents approaches a value of 1, expressed as a percentage, and approaches a value of 0 for individuals with arbitrarily remote common ancestors. Coefficient of relationship The coefficient of relationship r between two people B and C is obtained by a summation of coefficients calculated for every line by which they are connected to their identical ancestors point, common ancestors. Each such line ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consanguinity
Consanguinity (from Latin '':wikt: consanguinitas, consanguinitas'' 'blood relationship') is the characteristic of having a kinship with a relative who is descended from a common ancestor. Many jurisdictions have laws prohibiting people who are closely related by blood from Consanguine marriage, marrying or having sexual relations with each other. The degree of relationship, degree of consanguinity that gives rise to this prohibition varies from place to place. On the other hand, around 20% of the global population lives in areas where some consanguinous marriages are preferred. The degree of relationships are also used to determine heirs of an estate according to statutes that govern intestacy, intestate succession, which also vary from jurisdiction to jurisdiction. In some communities and time periods, cousin marriage is allowed or even encouraged; in others, it is taboo, and considered to be incest. The degree of relative consanguinity can be illustrated with a ''consanguinity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
