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Out-crossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful technique in animal breeding. The outcrossing breeder intends to remove the traits by using "new blood." With dominant traits, one can still see the expression of the traits and can remove those traits whether one outcrosses, line breeds or inbreeds. With recessive traits, outcrossing allows for the recessive traits to migrate across a population. Many traits are Mendelian and therefore exhibit a more complicated intermediate phenotype. The outcrossing breeder then may have individuals that have many deleterious genes that may be expressed by subsequent inbreeding. There is now a gamut of deleterious genes within each individual in many dog breeds. Increasing the variation of genes or alleles within the gene pool may protect against exti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syngamy
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally called fertilisation. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In Antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote in fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labradoodle
A Labradoodle () is a crossbreed dog created by crossing a Labrador Retriever and a Standard, Miniature, or Toy Poodle. The term dates back to at least 1955 but was unpopular at the time. Labradoodles are considered a good choice for people with canine dander allergies, since some have the same hypoallergenic coat as their poodle ancestors. The Australian Labradoodle Association of America, an organization run by Labradoodle breeders, says they are "generally considered healthy dogs". However, they also state that hip and elbow dysplasia are common problems affecting Labradoodles. Other ailments include eye diseases and Addison's disease. Wally Conron of Australia asserts that healthy Labradoodles are "few and far between" and most are "crazy or have a hereditary problem." He mistakenly took credit for naming the Labradoodle in 1989. The Labradoodle mix had been known in the United States since the 1950s and was used in the entertainment industry in the U.S. as early as the 196 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backcrossing
Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent. It is used in horticulture, animal breeding, and production of gene knockout organisms. Backcrossed hybrids are sometimes described with acronym "BC"; for example, an F1 hybrid crossed with one of its parents (or a genetically similar individual) can be termed a BC1 hybrid, and a further cross of the BC1 hybrid to the same parent (or a genetically similar individual) produces a BC2 hybrid. Plants Advantages * If the recurrent parent is an elite genotype, at the end of the backcrossing programme, an elite genotype is recovered. * As no "new" recombination results, the elite combination is not lost. Disadvantages * It works poorly for quantitative traits. * It is more restricted for recessive traits. * In practice, sections of genome from the nonrecurrent parents are often still present and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breeding
Breeding is sexual reproduction that produces offspring, usually animals or plants. It can only occur between a male and a female animal or plant. Breeding may refer to: * Animal husbandry, through selected specimens such as dogs, horses, and rabbits * Breeding in the wild, the natural process of reproduction in the animal kingdom * Sexual reproduction of plants * Plant breeding, through specimens selected by humans for desirable traits Science * Breeding refers to nuclear transmutations that produce fuel for further reactions, in a breeder reactor to become fissile material or in a fusion reactor to produce tritium, see Biology * Breeding (sex act) * Breeding back, a breeding effort to re-assemble extinct breed genes * Breeding pair, bonded animals who cooperate to produce offspring * Breeding program, a planned breeding of animals or plants * Breeding season, the period during each year when a species reproduces * Captive breeding, raising plants or animals in zoos or othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outbreeding Depression
In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. This is particularly likely if the subspecies have different habitats or if no genetic exchange has occurred, except in the distant past. The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously. The risks of outbreeding are on par with the risks of inbreeding, and these risks sometimes limits the potential for genetic rescue or augmentations. Indeed, studies that report hybridization in mammals find resulting negative consequences about 4 times more likely than positive consequences. Outbreeding depression can occur between an invasive population and a native populations; hybridization can result in extinction of the native species or the loss of native adaptations. Outbreeding depression considered post-zygotic response because outbreeding depression is noted usually in the performance of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterosis
Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. These effects can be due to Mendelian or non-Mendelian inheritance. Definitions In proposing the term heterosis to replace the older term heterozygosis, G.H. Shull aimed to avoid limiting the term to the effects that can be explained by heterozygosity in Mendelian inheritance. Heterosis is often discussed as the opposite of inbreeding depression, although differences in these two concepts can be seen in evolutionary considerations such as the role of genetic variation or the effects of genetic drift in small populations on these concepts. Inbreeding depression occurs when related parents have children with traits that negatively influence their fitness largely due to homozygosity. In such instances, outcrossing shoul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consanguinity
Consanguinity ("blood relation", from Latin '' consanguinitas'') is the characteristic of having a kinship with another person (being descended from a common ancestor). Many jurisdictions have laws prohibiting people who are related by blood from marrying or having sexual relations with each other. The degree of consanguinity that gives rise to this prohibition varies from place to place. Such rules are also used to determine heirs of an estate according to statutes that govern intestate succession, which also vary from jurisdiction to jurisdiction. In some places 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 table'' in which each level of lineal consanguinity (''generation'' or ''meiosis'') appears as a row, and individuals with a collaterally consanguineous relationship share the same row. The Knot System is a numerical notati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outbreeding Depression
In biology, outbreeding depression happens when crosses between two genetically distant groups or populations result in a reduction of fitness. This is particularly likely if the subspecies have different habitats or if no genetic exchange has occurred, except in the distant past. The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously. The risks of outbreeding are on par with the risks of inbreeding, and these risks sometimes limits the potential for genetic rescue or augmentations. Indeed, studies that report hybridization in mammals find resulting negative consequences about 4 times more likely than positive consequences. Outbreeding depression can occur between an invasive population and a native populations; hybridization can result in extinction of the native species or the loss of native adaptations. Outbreeding depression considered post-zygotic response because outbreeding depression is noted usually in the performance of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inbreeding Depression
Inbreeding depression is the reduced biological fitness which has the potential to result from inbreeding (the breeding of related individuals). Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. Inbreeding depression is often the result of a population bottleneck. In general, the higher the genetic variation or gene pool within a breeding population, the less likely it is to suffer from inbreeding depression, though inbreeding and outbreeding depression can simultaneously occur. Inbreeding depression seems to be present in most groups of organisms, but varies across mating systems. Hermaphroditic species often exhibit lower degrees of inbreeding depression than outcrossing species, as repeated generations of selfing is thought to purge deleterious alleles from populations. For example, the outcrossing nematode (roundworm) ''Caenorhabditis remanei'' has been demonstrated to suffer severely from inbreeding depression, unlike its he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such bacteria and archaea. However, some process in bacteria may be considered analogous to sexual reproduction in that they incorporate new genetic information, including bacterial conjugation, transformatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental concept in science. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey. Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. His studies at the University of Cambridge's Christ's Col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gregor Mendel
Gregor Johann Mendel, Augustinians, OSA (; cs, Řehoř Jan Mendel; 20 July 1822 – 6 January 1884) was a biologist, meteorologist, mathematician, Augustinians, Augustinian friar and abbot of St Thomas's Abbey, Brno, St. Thomas' Abbey in Brünn (''Brno''), Margraviate of Moravia. Mendel was born in a Sudeten Germans, German-speaking family in the Austrian Silesia, Silesian part of the Austrian Empire (today's Czech Republic) and gained posthumous recognition as the founder of the modern science of genetics. Though farmers had known for millennia that crossbreeding of animals and plants could favor certain desirable trait (biological), traits, Mendel's pea plant experiments conducted between 1856 and 1863 established many of the rules of biological inheritance, heredity, now referred to as the laws of Mendelian inheritance. Mendel worked with seven characteristics of pea plants: plant height, pod shape and color, seed shape and color, and flower position and color. Taking seed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
