OKLAHOMA ACADEMY OF SCIENCE 4<) 



like several somatic factor mutations in plants, because the charac- 

 ters in^'olve a mutation from a recessive gene to a dominant one. 



Tlie author has applied the mechanism of chromosome elimina- 

 tion to the observed results for these mosaics, but this is not essen- 

 tial to account for dominant elytral mosiacs in Bruchiist He be- 

 lieves that the most plausible explanation is to regard these thirty- 

 one dominant mosiacs as somatic mutations that originate in an 

 autosome on one side of the body of the female sometime durin.i,'- 

 its ontogeny. Since any mutation in a somatic tissue, if recessive. 

 would lie concealed by the presence of the normal allelomorph in 

 the homolozygous chromosome, only dominant mosaics were ob- 

 ser\ ed. 



It is evident that these soniatic mutations in Bruchus concern 

 the autosome in which the midtiple allelomorph genes for R (red) 

 is located, because it indicates that there is a chromosome continuit}- 

 between the gene R (red) in this autosome in the germ cell and this 

 same gene as manifested through its thirty-one mutations. Of these, 

 twenty somatic mutations occurred from recessive black to domi- 

 nant red from homozygous black cultures ; only one mosaic origi- 

 nated from a pure white culture through a mutation from recessive 

 white to dominant black ; while from the wild stocks, even mutated 

 fr(_)m recessive tan to dominant black, and only one from recessive 

 tan to dominant white. 



In conclusion, the most noteworthy result is that germinal and 

 somatic mutations are identical factor mutations because both irigi- 

 nate througli a mutation in the same chromosome. 



XXIII. A PRELIMINARY REPORT ON THE GENETICS 



OF A RED SPOTTED SEX LIMITED MUTATION 



BRUCHUS 



Clarence Lee Furrow. 



From the Zoological Laboratory of the University of Oklahoma. 

 Contribution No. 20, Second Series. 



This report is concerned- with the genetic behavior of a 'sex 

 limited' mutation which occurred in a stock of culture of Bruchus, 

 the four-spotted cowpea weevil. 



In the wild or normal stock tan is the common body color. The 

 female of the wild type carries four black spots, two on each 

 elytrum. The male is less conspicuous than the female, as he is 

 much smaller in size and does not have spotted elytra ; however, 

 the factors for body color and elytra pattern are carried by the 

 male even though they are not manifested somatically. 



During the year of 1917, while investigating a stock culture of 



