The Components of Genetic Variance in Populations of Biparental Progenies and Their Use in Estimating the Average Degree of Dominance

Biometrics ◽  
1948 ◽  
Vol 4 (4) ◽  
pp. 254 ◽  
Author(s):  
R. E. Comstock ◽  
H. F. Robinson
Keyword(s):  
Genetic Variance ◽  
Average Degree ◽  
Degree Of Dominance

scholarly journals THE GENETIC VARIABILITY OF THIRD CHROMOSOMES IN A LOCAL POPULATION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1976 ◽  
Vol 82 (1) ◽  
pp. 63-82
Author(s):  
Takao K Watanabe ◽  
Osamu Yamaguchi ◽  
Terumi Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Balancing Selection ◽  
Local Population ◽  
Load Ratio ◽  
Average Degree ◽  
Large Cage ◽  
Degree Of Dominance ◽  
Cage Population ◽  
The Difference ◽  
Lethal Genes

ABSTRACT Five hundred and two third chromosomes were extracted from a large cage population of Drosophila melanogaster initiated two months after collection of the progenitors near Raleigh, North Carolina in 1970.—Salivary gland chromosomes of 489 chromosome lines were examined and 54 chromosomes were found to carry inversions. The inversions were classified into three polymorphic types [In(3L)P, In(3R)P, and In(3R)C] and two unique types. The polymorphic inversions were found in frequencies of 0.012, 0.088, and 0.010, respectively.—Viabilities of homozygotes and heterozygotes were examined. Chromosomes with lethals occurred with a frequency of 0.495: 0.537 in the group of inversion-carrying chromosomes and 0.490 in the group of inversion-free chromosomes. The average homozygote viability computed on the basis of an average heterozygote viability of 1.0000 was 0.3235 if lethal lines were included and 0.6290 if they were excluded. The detrimental load to lethal load ratio (D:L ratio) was 0.70 (=0.4636-0.6650). The average viability of lethal heterozygotes was significantly larger than that of lethal-free heterozygotes. It appears, however, that lethal genes in heterozygotes have deleterious effects on fitness as a whole.—The average degree of dominance for viability polygenes was estimated to be about 0.3-0.4 in lethal-free individuals and nearly zero in lethal heterozygotes. Overdominance or some form of balancing selection was suggested at some loci. The difference between the values obtained for average degree of dominance due to genetic backgrounds and superior vibaility of lethal heterozygotes (but not fitness as a whole) suggests that some epistasis or coadaptation occurs.—The results described above are similar to those obtained for the second chromosomes (Mukai and Yamaguchi 1974).

scholarly journals REGIONS OF STABLE EQUILIBRIA FOR MODELS OF DIFFERENTIAL SELECTION IN THE TWO SEXES UNDER RANDOM MATING

Genetics ◽  
1977 ◽  
Vol 85 (1) ◽  
pp. 171-183
Author(s):  
J F Kidwell ◽  
M T Clegg ◽  
F M Stewart ◽  
T Prout
Keyword(s):  
Random Mating ◽  
Equilibrium Structure ◽  
Directional Selection ◽  
Average Degree ◽  
Weak Selection ◽  
Differential Selection ◽  
Degree Of Dominance ◽  
Stable Equilibria ◽  
Selection Intensities ◽  
The Stability

ABSTRACT The equilibrium structure of models of differential selection in the sexes is investigated. It is shown that opposing additive selection leads to stable polymorphic equilibria for only a restricted set of selection intensities, and that for weak selection the selection intensities must be of approximately the same magnitude in the sexes. General models of opposing directional selection, with arbitrary dominance, are investigated by considering simultaneously the stability properties of the trivial equilibria and the curve along which multiple roots appear. Numerical calculations lead us to infer that the average degree of dominance determines the equilibrium characteristics of models of opposing selection. It appears that if the favored alleles are, on the average, recessive, there may be multiple polymorphic equilibria, whereas only a single polymorphic equilibrium can occur when the favored alleles are, on the average, dominant. The principle that the average degree of dominance controls equilibrium behavior is then extended to models allowing directional selection in one sex with overdominance in the other sex, by showing that polymorphism is maintained if and only if the average fitness in heterozygotes exceeds one.

Four-year height growth variation among and within S0, S1 × S1, S1 open-pollinated, and S2 inbred jack pine families

1981 ◽  
Vol 11 (3) ◽  
pp. 654-661 ◽  
Author(s):  
Thomas D. Rudolph
Keyword(s):  
Inbreeding Depression ◽  
Genetic Variance ◽  
Tree Height ◽  
Jack Pine ◽  
Height Growth ◽  
Degree Of Dominance ◽  
Growth Variation ◽  
High Degree ◽  
Original Female

After 4 years, inbreeding depression in tree height of jack pine (Pinusbanksiana Lamb.) was from 18 to 24% in S2 (second selfed generation) progenies compared with S0 (original female parents) open-pollinated progenies. This indicates a high degree of dominance for height growth. Crosses between S1 (first selfed generation) lines and open-pollinated progenies from S1 trees showed heterosis and relief from inbreeding depression so that vigor was restored to at least the level of the ancestral S0 parents. Genetic variance among S2 progenies was greatly increased indicating that inbreeding increased heritability of height growth.

scholarly journals Гетерозис у кукурузы: к вопросу о преобладающем типе внутрилокусных взаимодействий

2021 ◽  
Author(s):  
Михаил Михайлов ◽  
Keyword(s):  
Genetic Analysis ◽  
Average Degree ◽  
Maize Productivity ◽  
The North ◽  
Degree Of Dominance ◽  
Heterosis Effect ◽  
Unbiased Estimates

Heterosis in maize: toward prevalence type of intralocus interactions. In the biometrical genetic analysis of maize productivity, performed according to the North Caroline III design, unbiased estimates were used to calculate the average degree of dominance, in which, on average, the effect of linkage was eliminated. The hybrids Rf7×Ku123, MK01×A619 were studied, and unbiased estimates were calculated for four more hybrids according to the literature data. For genes controlling productivity, unbiased estimates of the average degree of dominance ranged from 0.65 to 0.87 for different hybrids. The result indicates that the heterosis effect in maize is more likely to be caused by dominant interactions than over-dominant ones.

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.

The value of crossbreeding information in selection of poultry under a dominance model

1998 ◽  
Vol 66 (2) ◽  
pp. 519-528 ◽  
Author(s):  
P. Uimari ◽  
J. P. Gibson
Keyword(s):  
Genetic Variance ◽  
Pure Line ◽  
Dominance Model ◽  
Partial Dominance ◽  
Complete Dominance ◽  
Degree Of Dominance ◽  
Dominance Variation ◽  
Pure Lines ◽  
Selection Of ◽  
Better Than

AbstractA stochastic simulation was used to investigate the value of crossbreeding information in a two line crossbreeding system in poultry under different genetic scenarios. Populations consisted of 25 sires and 250 dams, which were mated to produce both purebred and crossbred progeny. The next generation parents were selected either based on purebred information (PLS) (sib means, and own performance for females) or additional crossbred sib means were included (CCPS). The trait under selection was controlled by 20 loci with varying degree of dominance. Pure lines differed in initial allele frequencies. If the trait was controlled by loci with partial dominance, little or no extra benefit was obtained from including crossbred information over the pure line information. Under complete dominance and overdominance CCPS outperformed PLS. As a practical rule, CCPS is better than PLS if the ratio between dominance variance and total genetic variance is around 0·3 or higher. In this case the most probable cause of the dominance variation is loci with full or overdominance.

scholarly journals GROWTH TRAIT'S AND YIELD EVAIUATION OF ITALIAN MAIZE INBRED LINES BY FULL DIALLEL CROSS

2017 ◽  
Vol 48 (3) ◽  
Author(s):  
Abed & et al.
Keyword(s):  
Reciprocal Cross ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Total Yield ◽  
Diallel Cross ◽  
Inbred Lines ◽  
Area Index ◽  
Positive Direction ◽  
Maize Inbred Lines ◽  
Degree Of Dominance

To evaluate five  maize inbred lines imported from Italy by  daillel and reciprocal crosses which predict from its, by estimate the heterosis ,general and specific combining ability effect(Gca,Sca,Rca), type of gene action and degree of dominance  for growth traits  and total yield. Field experiment was conducted during the two successive  seasons of 2013 , during spring  seasons full –diallel cross was carried out among inbred lines, In fall season a comparison experiment between the parents and the hybrids was carried by using randomized complete block design. The result show significant differences  for the  plant height (PH)(cm), ear height (EH)(cm) ,number of  leafs per plant(NLP) ,leaf area index(LA) ,the biomass(BI) and total yield per area(TY)(tan.h-1) which refer to high variation among the parents. The  inbred line Agostano  excel in TY (tan .h-1), NLP and  the BI, as such the DSP177  was excellence in ether traits  and the cross between  parents was deign high TY reach to 7.88 tan.h-1.The results of heterosis revealed the 20 cross in PH,15 cross in EH,14 cross in NLP and LAI, 17 cross in BI and 15 cross in TY  a positive direction desired for heterosis , best values for it  given from the  hybrid Hi39Antiguao x FLO1240 (128.9%) in TY . The genetic analyses emerged the greatest role of inheritable traits which to demonic effect and some for this inheritable to additive effect   where notes high significant for the GCA,SCA and RCA but the rate of the  Gca / Sca more loss  than one for all traits as well as the rate of Gca / Rca  except LAI in reciprocal cross which it more than one , as such the dominance genetic variance(δ2D)  which higher than the  additive genetic variance(δ2A), and high bored  sense heritability (h2bs%) ,and lower narrow  sense heritability (h2ns %)for the daillel cross all traits as well as the degree of dominance which more than one except the LA in reciprocal cross  , It can be conclude the possibility of benefit to breed the parents to produce diallel cross by  using the hybridization  method is the hybridization and  the  hybridization followed by selection to produce reciprocal cross  .

scholarly journals Inheritance of Resistance to Chlorpyrifos in the Mt Alford Strain and to Diazinon in the Gracemere Strain of the Cattle Tick (Boophilus micro plus)

1982 ◽  
Vol 35 (4) ◽  
pp. 427 ◽  
Author(s):  
BF Stone ◽  
NJ Youlton
Keyword(s):  
Average Degree ◽  
F1 Hybrids ◽  
Cattle Tick ◽  
Inheritance Of Resistance ◽  
Incomplete Dominance ◽  
Resistance Factors ◽  
Degree Of Dominance ◽  
Phenotype Analysis ◽  
Reciprocal Crossing ◽  
D Values

Reciprocal crossing of the Mt Alford (A) strain of the cattle tick B .. micro pius with a susceptible (8) strain and phenotype analysis of F 1, testcross and F 2 progeny showed that high chlorpyrifos resistance in strain A was due to two genes that were complementary and jointly exhibited incomplete dominance. Diazinon resistance in the Gracemere (G) strain appeared to be similarly inherited. The 'average' degree of dominance ('average dominance', D ?? ) of high chlorpyrifos resistance over susceptibility, exhibited by F 1 hybrids from A x 8 reciprocal crossings, was + 0�54 on a -1 to + 1 scale and was not significantly different from the parametric value of + O' 5 (semi-dominance). The corresponding D ?? values revealed by G x 8 crossings were + 0�42 for diazinon resistance (significantly less than +0'5) and -0,031 for chlorpyrifos resistance (not significantly different from zero and therefore exhibiting zero dominance/recessivity). Resistance factors for chlorpyrifos in strains A and G forhomozygotes were 74 and 35, respectively, and for F1 hybrids were 25-29 and 5-7, respectively. The resistance factors for diazinon in strain G for homozygotes and F1 hybrids were 174 and 37-41, respectively.

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