Genetics Genetics An acentric chromosome is a fragment of a chromosome (one of the microscopically visible carriers of the genetic material DNA) that is lacking a centromere (the "waist" of the chromosome essential for the division and the retention of the chromosome in the cell) and so is lost when the cell divides. ...more on Wikipedia about "Acentric chromosome"
Adam's Curse: A Story of Sex, Genetics, and the Extinction of Men is a book by Oxford University human genetics professor Bryan Sykes expounding his hypothesis that with the declining sperm count in men and the continual atrophy of the Y chromosome, within 5,000 generations (approximately 125,000 years) the male of the human species will become extinct. ...more on Wikipedia about "Adam's Curse"
The Alu family is a family of polymorphisms in the Human genome. ...more on Wikipedia about "Alu family"
Amplified fragment length polymorphism, or "AFLP", is a tool used in the study of genetics and in the practice of genetic engineering. ...more on Wikipedia about "Amplified fragment length polymorphism"
Aneuploidy is a chromosomal state where abnormal numbers of specific chromosomes or chromosome sets exist within the nucleus. ...more on Wikipedia about "Aneuploidy"
The Animal Genome Size Database is a comprehensive catalogue of published genome size estimates for vertebrate and invertebrate animals. It was created in 2001 by Dr. T. Ryan Gregory of the University of Guelph in Canada. As of Septermber 2005, the database contains data for over 4,000 species of animals. A similar database, the Plant DNA C-values Database ( C-value being analogous to genome size in diploid organisms) was created by researchers at the Royal Botanic Gardens, Kew, in 1997. ...more on Wikipedia about "Animal Genome Size Database"
Annealing, in genetics, means for DNA or RNA to pair by hydrogen bonds to a complementary sequence, forming a double-stranded polynucleotide. The term is often used to describe the binding of a DNA probe, or the binding of a primer to a DNA strand during a polymerase chain reaction (PCR). ...more on Wikipedia about "Annealing (biology)"
An asymptomatic carrier (or carrier), is a person who is infected with an infectious disease or carries the abnormal gene of a recessive genetic disorder, but displays no symptoms. Although unaffected by the disease or the disorder themselves, carriers can transmit it to others. ...more on Wikipedia about "Asymptomatic carrier"
Atavism in Physical Science ...more on Wikipedia about "Atavism"
An autosome is a non-sex chromosome. It is an ordinary paired chromosome that is the same in both sexes of a species. For example, in humans, there are 22 pairs of autosomes. The X and Y chromosomes are not autosomal. ...more on Wikipedia about "Autosome"
Auxology is a meta-term covering the study of all aspects of human physical growth; though it is also a fundamental of biology generally. Auxology is a highly multi-disciplinary science involving health sciences / medicine ( pediatrics, general practice, endocrinology, neuroendocrinology, physiology, epidemiology, and to a lesser degree other fields), nutrition, genetics, anthropology, anthropometry, ergonomics, history, economic history, economics, socioeconomics, sociology, public health, and psychology, among others. ...more on Wikipedia about "Auxology"
B chromosomes are small supernumerary chromosomes found in many eukaryotic nuclei that are believed to be largely non-coding and probably parasitic on the host genome. ...more on Wikipedia about "B chromosomes"
In those species in which sex is determined by the presence of the Y or W chromosome rather than the diploidy of the X or Z, a Barr body is the inactive X chromosome in a female cell, or the inactive Z in a male (Lyon, 2003), rendered inactive in a process called Lyonization. The Lyon hypothesis states that in cells with multiple X chromosomes, all but one is inactivated during mammalian embryogenesis. This happens early in embryonic development at random in mammals, (Brown, 1997) except in marsupials and in some extra-embryonic tissues of some placental mammals, in which the father's X chromosome is always deactivated (Lee, 2003). They're named for their discoverer, Murray Barr. ...more on Wikipedia about "Barr body"
In molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair (often abbreviated bp). In DNA, adenine (A) forms a base pair with thymine (T), as does guanine (G) with cytosine (C). In RNA, thymine is replaced by uracil (U). As DNA is usually double-stranded, the number of base pairs given for a particular DNA strand is the number of nucleotides in one of the strands. Thus, the following examples of base-paired nucleotide sequence are said to be six base-pairs long: ...more on Wikipedia about "Base pair" Whatever You're Into, Get Into www.shortopedia.com.
The Behavior Genetics Association promotes research into the connection between heredity and behavior. Its science journal is titled Behavior Genetics, "the leading journal concerned with the genetic analysis of complex traits." ...more on Wikipedia about "Behavior Genetics Association"
Behavioural genetics (behavioral genetics) is the field of biology that studies the role of genetics in animal behaviour. The field is an overlap of genetics, ethology and psychology (particularly evolutionary psychology). Classically, behavioural geneticists have studied the heritability of behavioural traits. ...more on Wikipedia about "Behavioural genetics"
Biological inheritance is the process by which an offspring cell or organism acquires or becomes predisposed to characteristics of its parent cell or organism. Through inheritance, variations exhibited by individuals can accumulate and cause a species to evolve. ...more on Wikipedia about "Biological inheritance"
A blood type is a description of an individual's characteristics of red blood cells due to substances ( carbohydrates and proteins) on the cell membrane. The two most important classifications to describe blood types in humans are ABO and the Rhesus factor (Rh factor). There are 46 other known antigens, most of which are much rarer than ABO and Rh. Blood transfusions from incompatible groups can cause an immunological transfusion reaction, resulting in hemolytic anemia, renal failure, shock, and death. ...more on Wikipedia about "Blood type"
Bookmarking is a biological phenomenon believed to function as an epigenetic mechanism for transmitting cellular memory of the pattern of gene expression in a cell through mitosis to its daughter cells. This is vital for maintaining the phenotype in a lineage of cells so that, for example, liver cells divide into liver cells and not some other cell type. It is characterized by non-compaction of some gene promoters during mitosis. In terms of mechanism, it is believed that a) sometime prior to the onset of mitosis the promoters of genes that exist in a transcription-competent state become "marked" in some way, b) that this "mark" persists through mitosis, and c) that the marking transmits gene expression memory by preventing the mitotic compaction of DNA at this locus, or by facilitating reassembly of transcription complexes on the promoter, or both. In some cases the bookmarking is mediated by binding of specific factors to the promoter prior to onset of mitosis, but in other cases could be mediated by patterns of histone modification or presence of histone variants that are characteristic of active genes, and which are believed to persist through mitosis. In the case of specific genes such as the stress-inducible hsp70 gene, bookmarking may also function as a mechanism for insuring that the gene can be transcribed early in G1 phase if a stress were to occur at that time. If this gene promoter were compacted it would take time to de-compact in G1 during which time the cell would be unable to transcribe this cytoprotective gene, leaving it vulnerable to stress-induced cell death. In this case, bookmarking appears to be important for cell survival. ...more on Wikipedia about "Bookmarking"
The C-value enigma is a term used to describe the complex puzzle surrounding the extensive variation in nuclear genome size among eukaryotic species. At the center of the C-value enigma is the observation that genome size does not correlate with organismal complexity. For example, many plant species and some single-celled protists, have genomes much larger than humans. ...more on Wikipedia about "C-value enigma"
A candidate gene is a gene, located in a chromosome region suspected of being involved in a disease, whose protein product suggests that it could be the disease gene in question. ...more on Wikipedia about "Candidate gene" Just http://www.shortopedia.com way Genetics
A cassette is a genetics term used to describe certain vectors that are normally used to confer a selectable marker on an organism. An example would be the kanMX cassette which confers kanamycin (an antibiotic) resistance upon bacteria or fungi. ...more on Wikipedia about "Cassette (genetics)"
The centromere is a region of a eukaryotic chromosome where the kinetochore is assembled. Thus, it is the site where spindle fibers of the mitotic spindle attach to the chromosome during mitosis. It is also the site of the primary constriction visible in microscopy images of chromosomes. Finally, it is the site at which a chromatid and its identical sister attach together during the process of cell reproduction. ...more on Wikipedia about "Centromere"
A chiasma, related to the Greek letter "X", is the technical term for the point where two chromatids are intertwined (interwoven) in a cell. The chiasmata are thought to be the points where two nonsister chromatids exchange genetic material during chromosomal crossover during meiosis(sister chromatids also form chiasmata between each other, but because their genetic material is identical, it doesn't cause any change in the resulting daughter cells). The chiasmata become visible during the diplonema stage of meiosis, but the actual "crossing-over" of genetic material is thought to occur during the previous pachytene Stage. When tetrads, which are composed of two pairs of sister chromatids, begin to split the only points of contact are at the chiasmata. ...more on Wikipedia about "Chiasma"
The Chillingham Wild Cattle represent a remarkable breed of cattle famous for their unique behaviour and apparent tolerance of heavy inbreeding. ...more on Wikipedia about "Chillingham Cattle"
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