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3. Gene complexes
Gene complexes, also called compound loci, consist of a number of functionally
related genes that are genetically closely linked. Whether composed of a few or
many genes, a gene complex should be assigned one symbol, in accordance with the
procedures described in section 2. The individual genes that compose gene complexes
may be designated by adding a hyphen (-) and an Arabic numeral to the locus designation.
For example, GluA1-1 and Glu-B1-1 designate, respectively, the
A-and B- genome genes that encode the x-type glutenin-1 proteins while Glu-A1-2
and Glu-B1-2 designate,respectively, the A- and B-genome genes that encode
the y-type glutenin-1 proteins. Different alleles of genes that are components
of gene complexes may be designated following the system described in section
2.3 but with the lower-case italic letter following the gene designation rather
than the locus designation.For example, Glu-A1 -1a designates the ChineseSpring
A genome allele that encodes the x -type glutenin-1 protein.
Triticeae enzyme and protein gene loci are commonly initially identified and assigned
designations based on studies of aneuploid strains that lack and/or contain extra
copies of whole chromosomes or telosomes. Consequently, evidence may be obtained
for the production of two or more similar enzyme or protein promoters by one chromosome
arm without genetic evidence as to whether or not the promoters are the products
of one gene, of different genes that are members of a gene complex, or of two
or more genes that are not members of one gene complex. In these situations, only
one locus designation for similar proteins or enzymes should be assigned to a
chromosome arm until recombination evidence indicates otherwise.
4. Phenotype Symbols
The basic symbol for a macromolecule should be identical to the basic symbol
for the locus or loci that encode the macromolecule (see Section 2.1) except
that each letter in the symbol should be a capital Roman letter. For a macromolecule
encoded by the members of a homologous set of loci, the phenotype symbol should
consist of the basic symbol followed by a hyphen (-) and the same Arabic numeral
as is contained in the genotype symbol. For example, the products of the
Adh-1 set of gene loci are designated ADH-1.
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