| Mendelian Inheritance in Man | A standard, comprehensive, perpetually updated reference source for traits in humans that have been shown to be mendelian or that are thought on reasonable grounds to be so. Each entry has a six-digit catalog number. Those securely established (by molecular biology or by extensive clinical studies) are marked with an asterisk. (05 Mar 2000) |
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| mitochondrial inheritance | The inheritance of a trait encoded in the mitochondrial genome. Because of the oddities of mitochondria, mitochondrial inheritance does not obey the classic rules of genetics. Persons with a mitochondrial disease may be male or female but they are always related in the maternal line and no male with the disease can transmit it to his children. (12 Dec 1998) |
| codominant inheritance | Inheritance in which two alleles are individually expressed in the presence of each other; there may be other alleles available at the locus that may or may not exhibit codominance. (05 Mar 2000) |
| collateral inheritance | The appearance of characters in collateral members of a family group, as when an uncle and a niece show the same character inherited from a common ancestor; in recessive characters it may appear irregularly, in contrast to dominant characters transmitted directly from one generation to the next. (05 Mar 2000) |
| mosaic inheritance | Inheritance in which the paternal influence is dominant in one group of cells and the maternal in another. Compare: lyonization. (05 Mar 2000) |
| multifactorial inheritance | Type of hereditary pattern seen with a combination of genetic factors, sometimes with environmental influence. Skin colour, for example, is multifactorially determined. (12 Dec 1998) |
| polygenic inheritance | Inheritance in which a measurable phenotype is generated by many loci, the contributions of which are statistically independent, additive, and of about equal value. (The latter are in accordance with the classical central limit therein and justify the use of the multivariate normal distribution in galtonian genetics). Synonym: polygenic inheritance. (05 Mar 2000) |
| cytoplasmic inheritance | <genetics> Inheritance of parental characters through a nonchromosomal means, thus mitochondrial DNA is cytoplasmically inherited since the information is not segregated at mitosis. In a broader sense the organisation of a cell may be inherited through the continuity of structures from one generation to the next. It has often been speculated that the information for some structures may not be encoded in the genomic DNA, particularly in protozoa that have complex patterns of surface organelles. See: maternal inheritance. (18 Nov 1997) |
| X-linked inheritance | The pattern of inheritance that may result from a mutant gene on an X chromosome. (05 Mar 2000) |
| holandric inheritance | Inheritance by genes on the y chromosome. Also called holandric inheritance. (12 Dec 1998) |
| hologynic inheritance | Transmission of a trait from mother to her daughters but to no sons, attributed to attached (partially fused) X chromosomes, to cytoplasmic inheritance, or to sex limitation with abnormal segregation, e.g., haematocolpos. (05 Mar 2000) |
| sex-influenced inheritance | Inheritance that is autosomal but has a different intensity of xpression in the two sexes, e.g., male pattern baldness. (05 Mar 2000) |
| sex-limited inheritance | Inheritance of a trait that can be expressed in one sex only, e.g., testicular feminization. (05 Mar 2000) |
| sex-linked inheritance | The pattern of inheritance that may result from a mutant gene located on either the X or Y chromosome. (05 Mar 2000) |
| nonMendelian inheritance | <genetics> In eukaryotes, patterns of gene transmission not explicable in terms of segregation, independent assortment and linkage. May be due to cytoplasmic inheritance, gene conversion, meiotic drive, etc. (18 Nov 1997) |