1259
Sterile mutants of Saccharomyces cerevisiae were isolated from alpha * cells having the a / alpha aar1 - 6 genotype ( exhibiting alpha mating ability and weak a mating ability as a result of a defect in a1 - alpha 2 repression ) .
 GENE: a / alpha aar1 - 6; GENE: a1 - alpha 2
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: a / alpha aar1 - 6; GENE: a1 - alpha 2