THE GENETIC STRUCTURE OF NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER. XIV. EFFECTS OF THE INCOMPLETE DOMINANCE OF THE IN(2LR)SM1 (Cy) CHROMOSOME ON THE ESTIMATES OF VARIOUS GENETIC PARAMETERS

Genetics ◽  
1980 ◽  
Vol 94 (1) ◽  
pp. 169-184
Author(s):  
Terumi Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Structure ◽  
Mutation Rate ◽  
Homologous Chromosome ◽  
Genetic Parameters ◽  
Natural Populations ◽  
Incomplete Dominance ◽  
Degree Of Dominance

ABSTRACT Recent reports (MUKAI et al. 1974; KATZand CARDELLINO1978; COCKER-HAM and MUEAI 1978) have indicated that the Cy chromosome is not always dominant over its homologous chromosome with respect to viability. Thus,the genetic parameters previously estimated using viabilities determined by the Cy method are biased. In the present paper, the biases of the estimates for the polygenic mutation rate, the degree of dominance and the homozygous load are examined. The results indicate that the biases for the mutation rate and the degree ofdominance are small and that the estimate of the homozygous load relative to the average viability of the population is not biased.

scholarly journals The genetic structure of natural populations of Drosophila melanogaster. XXIV. Effects of hybrid dysgenesis on the components of genetic variance of variability.

Genetics ◽  
1991 ◽  
Vol 127 (3) ◽  
pp. 545-552
Author(s):  
D S Suh ◽  
T Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Population Genetic ◽  
Genetic Parameters ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Natural Populations ◽  
Deleterious Mutations ◽  
Degree Of Dominance ◽  
Population Genetic Parameters ◽  
P Type

Abstract Eight hundred second chromosomes were extracted from the Ishigakijima population, one of the southernmost populations of Drosophila melanogaster in Japan. Half of them were extracted in Native cytoplasm (P-type), and half in Foreign cytoplasm (M-type). Various population-genetic parameters, including the frequency of lethal-carrying second chromosomes (Q = 0.235 for the Native; 0.218 for the Foreign), the allelism rate of lethal second chromosome (Ic = 0.0217 for the Native; 0.0134 for the Foreign), the homozygous detrimental and lethal loads (D = 0.179 for the Native; 0.270 for the Foreign; L = 0.262 for the Native; 0.240 for the Foreign), the average degree of dominance of mildly deleterious mutations (ĥE = 0.244 for the Native; 0.208 for the Foreign), and the components of genetic variance for viability [additive (sigma A2) and dominance (sigma D2)](ŝigma A2 = 0.0187 for the Native; 0.0172 for the Foreign; ŝigma D2 = 0.0005 for the Native; 0.0009 for the Foreign) were estimated. The data indicate that D was significantly larger and hE was significantly smaller in the Foreign cytoplasm. However, the estimates of additive and dominance variances were not significantly different between the two cytoplasms. The additive genetic variance for viability in the Ishigakijima population was greater than expected on the basis of mutation-selection balance confirming previous studies on papers of D. melanogaster in warm climates.

scholarly journals THE GENETIC STRUCTURE OF NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER. XVII. A POPULATION CARRYING GENETIC VARIABILITY EXPLICABLE BY THE CLASSICAL HYPOTHESIS

Genetics ◽  
1984 ◽  
Vol 108 (2) ◽  
pp. 393-408
Author(s):  
Shinichi Kusakabe ◽  
Terumi Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Structure ◽  
Genetic Variability ◽  
Natural Populations ◽  
Experimental Results ◽  
Effective Size ◽  
Degree Of Dominance ◽  
Significant Difference ◽  
Deleterious Genes ◽  
Classical Hypothesis

ABSTRACT About 400 second chromosomes were extracted from the Aomori population, a northernmost population of D. melanogaster on Honshu in Japan, and the following experimental results were obtained. (1) The frequency of lethal chromosomes was 0.23. (2) The effective size of the population was estimated to be about 3000, from the allelism rate of lethal chromosomes and their frequency. (3) The detrimental and lethal loads for viability were 0.243 and 0.242, respectively, and the D/L ratio became 1.00. (4) The average degree of dominance for mildly deleterious genes was estimated to be 0.178 ± 0.056. (5) Additive (α2  A) and dominance (α2  D) variances of viability were estimated to be 0.00276 ± 0.00090 and 0.00011 ± 0.00014, respectively. (6) There was no significant difference in environmental variances between homozygotes and heterozygotes. Using these estimates, we discuss the maintenance mechanisms of genetic variability of viability in the population. The mutation-selection balance explained these experimental results.

scholarly journals A SEASONAL SURVEY OF THE GENETIC STRUCTURE IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

1969 ◽  
Vol 44 (4) ◽  
pp. 247-258 ◽  
Author(s):  
KAZUHIKO KOSUDA ◽  
OSAMU KITAGAWA ◽  
DAIGORO MORIWAKI
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Structure ◽  
Natural Populations
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