Sex determination in bees. II. Additivity of maleness genes in Apis mellifera
Chaud-Netto, J.
Genetics 79(2): 213-217
1975
ISSN/ISBN: 0016-6731 PMID: 1132678 Document Number: 91876
The object of the study was to elucidate details of the genic balance between the sex genes in Apis mellifera. Twenty-two randomly taken morphological characters of A. m. adansonii were used in order to estimate the Mahalanobis generalised distance (D2) between: diploid drones (sexual constitution: 2m1 + 2m2 > X1X1 + ff); diploid workers (X1X2 + ff > 2m1 + 2m2); haploid drones (m1 + m2 > X1 + f); triploid workers (X1X1X2 + fff > 3m1 + 3m2). D2 is the numerical value of the possible major separation between two groups and measures the extent to which they differ in shape and size. The genes X and f (femaleness genes) have high additivity, since the effect of X1X2 ff is much greater than the effect of X1f, while the genes m (maleness genes) have small additivity. The distance between diploid drones and diploid workers was only 8% greater than the distance between haploid drones and diploid workers. Diploid drones are metamales (they are 8% more masculine than the haploid drones) and the greater maleness results from the m1/m1; m2/m2 maleness genes that are slightly additive in these males. Triploid workers are slightly masculinized (they are closer both to haploid and diploid drones than to diploid workers). The differences between triploid and diploid workers were very minute, indicating that the femaleness genes act in the same way in both types of females. The results indicate that the maleness genes of Apis mellifera have a small additivity. They also strengthen the hypothesis that X alleles are femaleness genes. J. Chaud-Netto.