| sexual generation | Reproduction by conjugation, or the union of male and female cells, as opposed to asexual generation. (05 Mar 2000) |
|---|---|
| skipped generation | A phenomenon of pedigrees in which a gene is transmitted from one affected person to another through a phenotypically unaffected person, as by recessivity (especially for X-linked traits), epistasis, variable expressivity, or absence of an environmental challenge such as a toxin. Except at a crass phenotypic level (e.g., clinical or commercial) this term becomes progressively less useful as the mechanisms are elucidated. (05 Mar 2000) |
| spontaneous generation | The obsolete hypothesis that living organisms can originate from nonliving matter. (09 Oct 1997) |
| nonsexual generation | Reproduction by fission, gemmation, or in any other way without union of the male and female cell, or conjugation. See: parthenogenesis. Synonym: heterogenesis, nonsexual generation. (05 Mar 2000) |
| f-1 generation | <genetics> Filial-One generation. The first generation of offspring which results after mating or genetically crossing two types of parents with different genotypes or phenotypes. (The parents are known as the P generation.) (09 Oct 1997) |
| f-2 generation | <genetics> Filial-Two generation. The generation of offspring which results from mating or genetically crossing members of the F-1 generation to each other. Members of this generation are two generations removed from the original parent generation, or the P generation. (09 Oct 1997) |
| filial generation | The offspring of a genetically specified mating: first filial generation (symbol F1), the offspring of parents of contrasting genotypes; second filial generation (F2), the offspring of two F1 individuals; third filial generation (F3), fourth filial generation (F4), etc., the offspring in succeeding generation's of continued inbreeding of F1 descendents. (05 Mar 2000) |