Birgid Schlindwein's
Hypermedia Glossary Of Genetic Terms
Search Results
Birgid Schlindwein'sHypermedia Glossary Of Genetic TermsSearch Results |
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| Segregation distortion | Deviation from the expected Mendelian proportion of individuals in a given genotypic class within a segregating population. Segregation distortion has been documented in a wide range of organisms, including plants, in which species or strain hybrids exhibit preferential dysfunction of gametes carrying one allelic class. |
| Genotype | The term proposed by Johannsen (1909) for the hereditary constitution of an individual, or of particular nuclei within its cells. |
| Segregation | The separation of allelic differences from one another. Segregation may occur at the first or second division of meiosis, or at the first mitosis after meiosis (postmeiotic segregation). Leading to new gene combinations (=recombination). |
| Population | A group of organisms of the same species relatively isolated from other groups of the same species. See deme. |
| Species | A group of organisms belong to the same biological species, if they are capable of interbreeding to produce fertile offspring. However the biological test of a species is not always available, and so there is also a morphological species concept based on anatomical similarities. |
| Hybrid | A cross-bred, heterozygot organism or cell, an individual from any cross involving parents of differing genotypes. Offspring of unlike parents.. In molecular genetics a DNA molecule with strands of different origin. Cf. hybridisation. |
| Gamete | Mature male or female reproductive cell (sperm or ovum) with a haploid set of chromosomes (23 for humans). |
| Allele | The term coined by Bateson and Saunders (1902) for characters which are alternative to one another in Mendelian inheritance (Gk. Allelon, one another; morphe, form). Now the term allele is used for two or more alternative forms of a gene resulting in different gene products and thus different phenotypes. In a haploid set of chromosomes there is only one allele at its specific locus. Diploid organisms have 2 alleles at a given locus, i.e. a normal and a mutant allele. A single allele for each gene locus is inherited separately from each parent (e.g., at a locus for eye colour the allele might result in blue or brown eyes). An organism is homozygous for a gene if the alleles are identical, and heterozygous if they are different. |