iga11e_ch103

Appendix A

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Appendix A

Genetic Nomenclature

There is no universally accepted set of rules for naming genes, alleles, protein products, and associated phenotypes. At first, individual geneticists developed their own symbols for recording their work. Later, groups of people working on any given organism met and decided on a set of conventions that all would use. Because Drosophila was one of the first organisms to be used extensively by geneticists, most of the current systems are variants of the Drosophila system. However, there has been considerable divergence. Some scientists now advocate a standardization of this symbolism, but standardization has not been achieved. Indeed, the situation has been made more complex by the advent of DNA technology. Whereas most genes previously had been named for the phenotypes produced by mutations within them, the new technology has shown the precise nature of the products of many of these genes. Hence, it seems more appropriate to refer to them by their cellular function. However, the old names are still in the literature, so many genes have two parallel sets of nomenclature.

The following examples by no means cover all the organisms used in genetics, but most of the nomenclature systems follow one of these types.

Drosophila melanogaster (insect)

ry	A gene that when mutated causes rosy eyes
ry⁵⁰²	A specific recessive mutant allele producing rosy eyes in homozygotes
ry⁺	The wild-type allele of rosy
ry	The rosy mutant phenotype
ry⁺	The wild-type phenotype (red eyes)
RY	The protein product of the rosy gene
XDH	Xanthine dehydrogenase, an alternative description of the protein product of the rosy gene; named for the enzyme that it encodes
D	Dichaete; a gene that when mutated causes a loss of certain bristles and wings to be held out laterally in heterozygotes and causes lethality in homozygotes
D³	A specific mutant allele of the Dichaete gene
D⁺	The wild-type allele of Dichaete
D	The Dichaete mutant phenotype
D⁺	The wild-type phenotype
D	(Depending on context) the protein product of the Dichaete gene (a DNA-binding protein)

Neurospora crassa (fungus)

arg	A gene that when mutated causes arginine requirement
arg-1	One specific arg gene
arg-1	An unspecified mutant allele of the arg gene
arg-1 (1)	A specific mutant allele of the arg-1 gene
arg-1⁺	The wild-type allele
arg-1	The protein product of the arg-1⁺ gene
Arg⁺	A strain not requiring arginine
Arg⁻	A strain requiring arginine

Saccharomyces cerevisiae (fungus)

ARG	A gene that when mutated causes arginine requirement
ARG1	One specific ARG gene
arg1	An unspecified mutant allele of the ARG gene
arg1-1	A specific mutant allele of the ARG1 gene
ARG1⁺	The wild-type allele
ARG1p	The protein product of the ARG1⁺ gene
Arg⁺	A strain not requiring arginine
Arg⁻	A strain requiring arginine

Homo sapiens (mammal)

ACH	A gene that when mutated causes achondroplasia
ACH1	A mutant allele (dominance not specified)
ACH	Protein product of ACH gene; nature unknown
FGFR3	Recent name for gene for achondroplasia
FGFR3¹ or FGFR31 or FGFR3* <1>	Mutant allele of FGFR3 (unspecified dominance)
FGFR3 protein	Fibroblast growth factor receptor 3

Mus musculus (mammal)

Tyrc	A gene for tyrosinase
+^Tyrc	The wild-type allele of this gene
Tyrc^ch or Tyrc-ch	A mutant allele causing chinchilla color
Tyrc	The protein product of this gene
+TYRC	The wild-type phenotype
TYRCch	The chinchilla phenotype

Escherichia coli (bacterium)

lacZ	A gene for utilizing lactose
lacZ⁺	The wild-type allele
lacZ1	A mutant allele
LacZ	The protein product of that gene
Lac⁺	A strain able to use lactose (phenotype)
Lac⁻	A strain unable to use lactose (phenotype)

Arabidopsis thaliana (plant)

YGR	A gene that when mutant produces yellow-green leaves
YGR1	A specific YGR gene
YGR1	The wild-type allele
ygr1-1	A specific recessive mutant allele of YGR1
ygr1-2D	A specific dominant (D) mutant allele of YGR1
YGR1	The protein product of YGR1
Ygr⁻	Yellow-green phenotype
Ygr⁺	Wild-type phenotype

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