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In biology a hybrid, also known as cross breed, is the result of mixing, through sexual reproduction, two animals or plants of different breeds, varieties, species or genera.〔(【引用サイトリンク】url=http://www.merriam-webster.com/dictionary/hybrid?show=0&t=1402607220 )〕 Using genetic terminology, it may be defined as follows.〔Rieger, R.; Michaelis A.; Green, M. M. (1991). ''Glossary of Genetics'' (5th ed.). Springer-Verlag. ISBN 0-387-52054-6 page 256〕 # Hybrid generally refers to any offspring resulting from the breeding of two genetically distinct individuals, which usually will result in a high degree of heterozygosity, though hybrid and heterozygous are not, strictly speaking, synonymous. # a genetic hybrid carries two different alleles of the same gene # a structural hybrid results from the fusion of gametes that have differing structure in at least one chromosome, as a result of structural abnormalities # a numerical hybrid results from the fusion of gametes having different haploid numbers of chromosomes # a permanent hybrid is a situation where only the heterozygous genotype occurs, because all homozygous combinations are lethal. From a taxonomic perspective, hybrid refers to: # Offspring resulting from the interbreeding between two animal species or plant species.〔Keeton, William T. 1980. Biological science. New York: Norton. ISBN 0-393-95021-2 page A9.〕 See also hybrid speciation. # Hybrids between different subspecies within a species (such as between the Bengal tiger and Siberian tiger) are known as intra-specific hybrids. Hybrids between different species within the same genus (such as between lions and tigers) are sometimes known as interspecific hybrids or crosses. Hybrids between different genera (such as between sheep and goats) are known as intergeneric hybrids. Extremely rare interfamilial hybrids have been known to occur (such as the guineafowl hybrids).〔Ghigi A. 1936. "Galline di faraone e tacchini" Milano (Ulrico Hoepli)〕 No interordinal (between different orders) animal hybrids are known. # The third type of hybrid consists of crosses between populations, breeds or cultivars within a single species. This meaning is often used in plant and animal breeding, where hybrids are commonly produced and selected, because they have desirable characteristics not found or inconsistently present in the parent individuals or populations. ==Etymology== The term hybrid is derived from Latin ''hybrida'', meaning the "offspring of a tame sow and a wild boar", "child of a freeman and slave", etc.〔(askoxford.com )〕 The term came into popular use in English in the 19th century, though examples of its use have been found from the early 17th century.〔Oxford English Dictionary Online, Oxford University Press 2007.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hybrid (biology)」の詳細全文を読む スポンサード リンク
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