Dictionary — 175 — International Rules 



Symbols for genes of standard type. — Generally _{-; for 

 definite genes preferably the gene symbol with -|- as a superscript. 



Symbols for other genes. — The smallest possible number of 

 the initial letters of the name for the character for which latin is 

 recommended when possible. 



Indicating dominant and recessive. — Dominant capital initial 

 letter; recessive small letter. 



Multiple alleles. — The symbol of the first discovered allele, 

 in small letters if recessive to standard type, with a capital initial 

 letter if dominant to it. The standard type is designated by the same 

 symbol with -j- as superscript; the others by the same symbol with 

 a special superscript in capitals for dominant, in small letters if 

 recessive as compared to the first allele. 



Polymeric (multiple) genes. — Genes which cannot be dis- 

 tinguished by the effects and for which the loci are not known, are 

 symbolized by the same symbol with different Arabic figures as 

 subscript Ai, Aj, A3, or by the same symbol with the Roman figure 

 of the chromosome as subscript Aj, An, Anj. 



Lethal genes are indicated by the greek letter Lambda (X) which 

 should be reserved for them, eventually as a subscript to another 

 symbol, or separate combined with an Arabian figure with a Roman 

 figure for the number of the chromosome, both as a subscript (Xi, 

 Xs, Xjiv, etc.). 



Genes in polyploids. — When the chromosomes form poly- 

 valents or if they pair at random, or if the segregation follows auto- 

 polyploid ratios, then the genes are written as many times as they 

 are present, AAAa, AAaa, Aaaa, etc. 



Groups of linked genes. — The genes written in order from 

 left to right in the chromosome and the symbols spaced II A b c D; 

 between those of different chromosomes a semicolon (;). 



Genes in related species. — The same symbol but with a sub- 

 script of the abbreviaton of the specific name. 



Formulae. — Generally AABbCc, but if parental gametic geno- 

 types are known ABc/AbC and if a linkage group is concerned and 



the loci of the different genes are known ^ ^ , the female gametic 

 genotypes being mentioned first. 



Reciprocal crosses. — In case plasmatic inheritance is involved 

 an abbreviation of the name of the mother in parenthesis before the 

 genotypic formula. 



Priority shall be valid if no essential objection to the symbol can 

 be made. 



Lettertypes. — Italics for symbols of genes; roman letters for 

 chromosome aberrations and rearrangements. 



