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Genetics Definitions
Term | Definition |
---|---|
allele | an alternative version of a gene |
locus | specific position on a chromosome occupied by a specific gene |
crossing over | where non-sister chromatids exchanged alleles during prophase I of meiosis |
genotype | alleles present within cells of an individual, for a particular trait |
phenotype | observable characteristics of an organism |
recessive | characteristic in which the allele responsible is only expressed in the phenotype if there is no dominant allele present |
co-dominant | a characteristic where both alleles contribute to the phenotype |
linkage | genes for different characteristics that are present at different loci on the same chromosome are linked |
genome | all the genetic information within an organism/cell |
bivalent | a pair of joined homologous chromosomes during prophase and metaphase of meiosis I |
chiasmata | the points where non-sister chromatids within a bivalent join, where they cross over |
complementary genes | genes that interact together to given the expression of a single characteristic |
dominant | characteristic in which the allele responsible is expressed in the phenotype even in those with heterozygous genotypes |
DNA mutation | a change to the DNA structure |
epistasis | the interaction of genes concerned with the expression of one gene |
gene | a length of DNA that codes for one or more polypeptides |
gene pool | total genetic information possessed by the reproductive members with a population of organisms |
genomics | the study of the whole set of genetic information in the form of DNA base sequences that occur in the cells of an organism of a particular species |
homeobox genes | genes that control the development of the body plan of an organism |
monogenic | characteristic coded for by one gene |
operon | a unit consisting of genes that work together under the control of an operator gene |
polyploid | eukaryotic organisms or cell with more than two sets of chromosomes |