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Epistasis
Epistasis is a phenomenon in genetics in which the effect of a gene mutation is dependent on the presence or absence of mutations in one or more other genes, respectively termed modifier genes. In other words, the effect of the mutation is dependent on the genetic background in which it appears. Epistatic mutations therefore have different effects on their own than when they occur together. Originally, the term ''epistasis'' specifically meant that the effect of a gene variant is masked by that of a different gene. The concept of ''epistasis'' originated in genetics in 1907 but is now used in biochemistry, computational biology and evolutionary biology. The phenomenon arises due to interactions, either between genes (such as mutations also being needed in regulators of gene expression) or within them (multiple mutations being needed before the gene loses function), leading to non-linear effects. Epistasis has a great influence on the shape of evolutionary landscapes, which lea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Genetics
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure. Population genetics was a vital ingredient in the emergence of the modern evolutionary synthesis. Its primary founders were Sewall Wright, J. B. S. Haldane and Ronald Fisher, who also laid the foundations for the related discipline of quantitative genetics. Traditionally a highly mathematical discipline, modern population genetics encompasses theoretical, laboratory, and field work. Population genetic models are used both for statistical inference from DNA sequence data and for proof/disproof of concept. What sets population genetics apart from newer, more phenotypic approaches to modelling evolution, such as evolutionary game theory and adaptive dynamics, is its emphasis on such genetic phenomena as dominance, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominance (genetics)
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes (autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication ( translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics ( phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florence Margaret Durham
Florence Margaret Durham (6 April 1869 – 25 June 1949) was a British geneticist at Cambridge in the early 1900s and an advocate of the theory of Mendelian inheritance, at a time when it was still controversial. She was part of an informal school of genetics at Cambridge led by her brother-in-law William Bateson. Her work on the heredity of coat colours in mice and canaries helped to support and extend Mendel's law of heredity. It is also one of the first examples of epistasis. National Institute for Medical Research Early life and education Florence Margaret Durham was born in 1869 in London, one of six daughters of surgeon Arthur Edward Durham (1833–1895) and his wife Mary Ann Cantwell. Her father was an alcoholic and her mother was strongly opposed to alcohol. In 1891 and 1892, Florence Durham achieved second class honours in the Natural Sciences Tripos Part I and II (physiology) at Girton College. From 1893 to 1899 she lectured in Biology at Royal Holloway College and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypostatic Gene
A hypostatic gene is one whose phenotype is altered by the expression of an allele at a separate locus, in an epistasis event. Example: In labrador retrievers, the chocolate coat colour is a result of homozygosity for a gene that is epistatic to the "black vs. brown" gene. The alleles determining whether the dog is black or brown, are that of the ''hypostatic gene'' in this event. See also * Epistasis * Bombay phenotype Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second-m ... References Further reading {{cite book , last = Hartwell , first = Leland , author2=L. Hood , author3=M. Goldberg , author4=A. Reynolds , author5=L. Silver , author6=R. Veres , title = Genetics: From Genes to Genomes , publisher = McGraw-Hill , date = 2004 , location = New York, NY , pag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Bateson
William Bateson (8 August 1861 – 8 February 1926) was an English biologist who was the first person to use the term genetics to describe the study of heredity, and the chief populariser of the ideas of Gregor Mendel following their rediscovery in 1900 by Hugo de Vries and Carl Correns. His 1894 book ''Materials for the Study of Variation'' was one of the earliest formulations of the new approach to genetics. Early life and education Bateson was born 1861 in Whitby on the Yorkshire coast, the son of William Henry Bateson, Master of St John's College, Cambridge. He was educated at Rugby School and at St John's College, where he graduated BA in 1883 with a first in natural sciences. Taking up embryology, he went to the United States to investigate the development of ''Balanoglossus'', a worm-like hemichordate which led to his interest in vertebrate origins. In 1883–4 he worked in the laboratory of William Keith Brooks, at the Chesapeake Zoölogical Laboratory in Hampton, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygenic Inheritance
A quantitative trait locus (QTL) is a locus (section of DNA) that correlates with variation of a quantitative trait in the phenotype of a population of organisms. QTLs are mapped by identifying which molecular markers (such as SNPs or AFLPs) correlate with an observed trait. This is often an early step in identifying the actual genes that cause the trait variation. Definition A quantitative trait locus (QTL) is a region of DNA which is associated with a particular phenotypic trait, which varies in degree and which can be attributed to polygenic effects, i.e., the product of two or more genes, and their environment. . These QTLs are often found on different chromosomes. The number of QTLs which explain variation in the phenotypic trait indicates the genetic architecture of a trait. It may indicate that plant height is controlled by many genes of small effect, or by a few genes of large effect. Typically, QTLs underlie continuous traits (those traits which vary continuous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muriel Wheldale Onslow
Muriel Wheldale Onslow (31 March 1880 – 19 May 1932) was a British biochemist, born in Birmingham, England. She studied the inheritance of flower colour in the common snapdragon Antirrhinum and the biochemistry of anthocyanin pigment molecules. She attended the King Edward VI High School in Birmingham and then matriculated at Newnham College, Cambridge in 1900. At Cambridge she majored in botany. Onslow later worked within Bateson's genetic group and then Frederick Gowland Hopkins biochemical group in Cambridge, providing her with expertise in biochemical genetics for investigating the inheritance and biosynthesis of petal colour in Antirrhinum. She was one of the first women appointed as a lecturer at Cambridge, after moving to the Biochemistry department. Education and personal life She was the only child of her parents John and Fannie (née Hayward) Wheldale. Her father was a solicitor. She attended King Edward VI High School in Birmingham, which was well known amongst s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biochemistry
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research.Voet (2005), p. 3. Biochemistry focuses on understanding the chemical basis which allows biological molecules to give rise to the processes that occur within living cells and between cells, Karp (2009), p. 2. in turn relating greatly to the understanding of tissues and organs, as well as organism structure and function. Miller (2012). p. 62. Biochemistry is closely related to molecular biology, which is the study of the molecular mechanisms of biological phenom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded to study the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the cell, the organism (e.g. dominance), and within the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
