TWO-WAY SELECTION ON PUPAL WEIGHT WITH DIFFERENT DEGREES OF INBREEDING IN TRIBOLIUM CASTANEUM

1974 ◽  
Vol 16 (4) ◽  
pp. 765-775 ◽  
Author(s):  
P. Y. Jui ◽  
G. W. Friars
Keyword(s):  
Tribolium Castaneum ◽  
Linear Response ◽  
Significant Interaction ◽  
Pupal Weight ◽  
Base Population ◽  
Significant Progress ◽  
Selected Lines ◽  
Selection Limit ◽  
Selection For ◽  
Seven Generations

Responses to selection for high and low pupal weight in Tribolium castaneum under four different inbreeding systems and two different relative humidities (40 and 70%) were observed for seven generations. By the seventh generation, the coefficients of inbreeding ranged from 0.79 in the full sib lines to 0.12 in the control lines.Heritability of pupal weight estimated by mid-parent offspring regression from the base population was around 0.30 which is lower than the estimates obtained by Bell (1969). However, realized heritabilities were around 0.50. Significant progress was observed for both upward and downward selection. A linear response in pupal weight was observed for most of the selected lines, suggesting that the selection limit had not been reached.Inbreeding caused a reduction of approximately two offspring per 10% increment in the inbreeding coefficient.Asymmetric responses were noted in conjunction with the significant interaction of the degree of inbreeding and the direction of selection.

scholarly journals The number of loci affecting a quantitative trait in Drosophila melanogaster revealed by artificial selection

1983 ◽  
Vol 42 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Araceli Gallego ◽  
Carlos López-Fanjul
Keyword(s):  
Initial Response ◽  
Selection Method ◽  
Base Population ◽  
Response To Selection ◽  
Family Selection ◽  
Selected Lines ◽  
Additive Variance ◽  
Bristle Number ◽  
Selection Limit ◽  
Selection For

SUMMARYIndividual and within-full-sib family selection for low sternopleural bristle number was carried out for 17 generations, with six replicate lines for each selection method. Our results can be summarized as follows: (1) the response to selection was exhausted very quickly, (2) the additive variance of the selected lines declined rapidly, (3) the variation in response to selection decreased as selection progressed, (4) genetic differences among replicates at the selection limit were small, (5) individual selection resulted in a higher initial response than within-family selection, but similar limits were achieved with both procedures. These observations are consistent with the hypothesis that the pattern of response to selection is due to the segregation in the base population of only a few loci with large effects, at intermediate frequencies.

Realized genetic parameters from an antagonistic selection index in Tribolium castaneum

1986 ◽  
Vol 28 (3) ◽  
pp. 358-364 ◽  
Author(s):  
J. L. Campo ◽  
L. G. Raya
Keyword(s):  
Genetic Correlation ◽  
Tribolium Castaneum ◽  
Selection Index ◽  
Selection Response ◽  
Pupal Weight ◽  
Base Population ◽  
Adult Weight ◽  
Antagonistic Selection ◽  
Individual Trait ◽  
Highly Correlated

Simultaneous selection of two highly correlated traits was practiced in Tribolium castaneum in a replicated experiment for six generations. Two lines were selected in each of three replicates: P+A− for an antagonistic selection index to increase pupal weight at 21 days and decrease adult weight at 31 days, and P−A+ for an antagonistic selection index to decrease pupal weight and increase adult weight. Genetic correlation between pupal and adult weights estimated in the base population was 0.95. Estimates of realized heritabilities and genetic correlation were obtained and compared with full-sib estimates. For the aggregate genotype, the P+A− line had a significant positive selection response, while the P−A+ line showed a significant negative response as would be expected. The response to divergent selection was asymmetrical, being less for the low pupal weight and high adult weight line than vice versa. Less asymmetry was found for the realized heritability, which agreed very well with the index heritability estimated in the base population. Both individual traits changed in the same direction, increasing for the P+A− line and decreasing for P−A+ line, even though a significant response was found only for pupal weight in the P+A− line. Therefore, the response to antagonistic selection for each individual trait seems to be heavily controlled by the strength of the genetic correlation between them. The realized genetic correlation between pupal weight and adult weight obtained from antagonistic selection index was in excellent agreement with full-sib estimates. Realized heritabilities for each trait were overestimated, especially for adult weight, even though there were essentially no differences between realized and estimated values.Key words: selection (artificial), antagonistic index, parameters (realized), Tribolium.

scholarly journals The effects of inbreeding and artificial selection on reproductive fitness

1962 ◽  
Vol 3 (1) ◽  
pp. 110-138 ◽  
Author(s):  
B. D. H. Latter ◽  
Alan Robertson
Keyword(s):  
Artificial Selection ◽  
Large Population ◽  
Theoretical Models ◽  
Base Population ◽  
Selected Lines ◽  
Index Method ◽  
Competitive Index ◽  
Sib Mating ◽  
Selection For ◽  
Rate Of Decline

The competitive-index method of measurement of over all fitness in Drosophila has been used to measure the effect of inbreeding and of artificial selection for metric characters in a large population of Drosophila melanogaster. The technique itself was examined in detail with particular reference to its repeatability and to the effect on it of the modification of various environmental variables.With continued full-sib mating the decline in the competitive index was very rapid (it was reduced to a half by a single generation of full-sib mating) and there were no indications that interactions between deleterious genes at different loci were important in determining the rate of decline of fitness as inbreeding increased. Other unselected lines with ten pairs of parents in each generation were carried to serve as a control for the lines under artificial selection. At the same theoretical degree of inbreeding the control lines had a much higher average fitness than the lines produced by continued full-sib mating.From the base population lines were selected in both directions for abdominal bristles, sternopleural bristles and for wing length, there being two replicates in all cases. Four control lines were kept with the same number of parents as the selected lines. In all cases the selected lines declined in fitness below the value for the base population. However, in three of the lines the fitness was not significantly below the value for the control lines. The effect of artificial selection on fitness was asymmetrical, the decline being greater with down selection for all characters.The relevance of these results to various theoretical models is discussed. If the variation in these characters is actively maintained in the base population by the selection of heterozygotes then the results are consistent with an average selection disadvantage of homozygotes relative to heterozygotes of about 0·5%.

Mating frequency in male Japanese quail: crosses among selected and unselected lines

1983 ◽  
Vol 25 (5) ◽  
pp. 450-456 ◽  
Author(s):  
D. E. Bernon ◽  
P. B. Siegel
Keyword(s):  
Genetic Variation ◽  
Mating Behavior ◽  
Japanese Quail ◽  
Mating Frequency ◽  
Base Population ◽  
Selected Lines ◽  
Gland Size ◽  
Parental Lines ◽  
Selection For ◽  
Cloacal Gland

The genetics of mating behavior in Japanese quail was investigated in replicated lines selected for high or low number of completed matings and the random bred control which served as the base population for the selected lines. Comparisons involved the parental lines, F1, F2, and backcross generations. Results indicate that mating frequency is influenced by additive and nonadditive genetic variation with the former being the primary heritable influence. The relationships between mating behavior, cloacal gland size, and relative aggressiveness suggest that selection for mating frequency influences factors commonly affecting these traits.

scholarly journals FOOD CONSUMPTION, FEED EFFICIENCY, METABOLIC RATE AND UTILIZATION OF GLUCOSE IN LINES OF TRIBOLIUM CASTANEUM SELECTED FOR 21-DAY PUPA WEIGHT

Genetics ◽  
1976 ◽  
Vol 83 (2) ◽  
pp. 393-407 ◽  
Author(s):  
Juan F Medrano ◽  
G A E Gall
Keyword(s):  
Metabolic Rate ◽  
Food Consumption ◽  
Tribolium Castaneum ◽  
Feed Efficiency ◽  
Large Body ◽  
Biological Efficiency ◽  
Growth Stages ◽  
Control Line ◽  
Selected Lines ◽  
Selection For

ABSTRACT Food consumption, feed efficiency, metabolic rate and glucose utilization were studied throughout development in one control (1C) and three selected lines (3, 9, 10) of Tribolium castaneum that had been subjected to long term selection for 21-day pupae weight. Growth rate, body composition, cellular growth and the activity of four dehydrogenase enzymes in the same lines have been reported (Medrano and Gall 1976).—Larva of selected lines consumed 1.2 times as much food as the control and gained an average of 2.9 times as much weight. The rapid growth of the selected lines was associated with a gross feed efficiency 20 to 30% above that for the control line. There was also a small but consistent improvement in the conversion of digested food. Average digestibility was higher for selected lines.—There was little apparent differentiation between the control and selected lines in metabolic rate/individual, but the rate measured on a per-unit weight basis was two- to three-fold greater for the control during the active growth stages. Respiratory quotients (R.Q.) of 1.0, indicative of carbohydrate oxidation, were observed through larval growth in all lines. Pupae at 21 days showed R.Q. values greater than 1.0, which were interpreted as resulting from a phenomenon in insects in which CO2 is released by pupae, in large bursts at irregular intervals. The rate constant of glucose oxidation, measured as the rate of C14 labelled CO2 respired during 2- to 6-hour incubation periods, was two- to three-fold higher in the control. In addition, the control line larvae expired 5% to 17% more of the ingested C14 as CO2. It was apparent that control line individuals maintained a much more active turnover of metabolites but without an effective retention of carbon as body substances. The results are discussed in support of the hypothesis that selection for large body size resulted in improved control mechanisms that influence the biological efficiency of growth in Tribolium.

COMPONENTS OF GROWTH IN GENETICALLY DIVERSE POPULATIONS OF TRIBOLIUM CASTANEUM

1969 ◽  
Vol 11 (4) ◽  
pp. 896-907 ◽  
Author(s):  
DuWayne C. Englert ◽  
A. E. Bell
Keyword(s):  
Tribolium Castaneum ◽  
Adult Emergence ◽  
Pupal Weight ◽  
Diverse Populations ◽  
Correlated Responses ◽  
Larval Weight ◽  
Developmental Patterns ◽  
Adult Weight ◽  
Total Growth ◽  
Selection For

The growth and developmental patterns of 19 genetically diverse populations of Tribolium castaneum were examined. Measurements were obtained on three primary traits (13-day larval weight, pupation time and pupal weight) and three secondary traits (number of larval molts, adult emergence time and adult weight). The populations were chosen on the basis of their previous selection histories. Selection for different primary traits produced profound effects upon the total growth and development complex.Genetic and environmental relationships between primary traits were estimated within each population, and a consistent asymmetry of correlated responses was observed to be determined by the direction of selection.Possible effects upon the disruption of an intricate balance of the three metamorphosis hormones (activation, molting and juvenile) through selection were postulated.

EFFECT OF SELECTION FOR GROWTH AND FOR BREAST DEVELOPMENT ON KEEL DEFECTS IN BROILERS

1962 ◽  
Vol 42 (2) ◽  
pp. 203-210 ◽  
Author(s):  
E. S. Merritt ◽  
M. Zawalsky ◽  
R. D. Crawford ◽  
S. B. Slen
Keyword(s):  
Lower Incidence ◽  
Breast Development ◽  
Base Population ◽  
Control Strain ◽  
Selected Lines ◽  
The Third ◽  
Definite Relationship ◽  
Rate Of Growth ◽  
Selection For

Data from the third and fourth generations of a number of lines selected exclusively for growth, and of a number selected solely for breast angle, showed that selection for these traits had an effect on the incidence of crooked keels and breast blisters in 63-day-old broilers. The base population of these selected lines was a meat-control strain and a sample of this strain was reared with each hatch of the selected lines.Lines selected for growth had the highest incidence of both crooked keels and breast blisters. The lines selected for breast angle had a lower incidence of these defects than the controls, even though they did not differ from the controls in 63-day weight. It was concluded that there is a definite relationship between rate of growth, breast development and the incidence of keel defects. Market grading data on a sample of birds from these lines reflected these differences in keel defects. The market grades for conformation were lowest in the growth lines and highest in the breast lines.

The effects of alternated cycles of full-sib and random mating on selection for pupa weight in Tribolium castaneum

1985 ◽  
Vol 27 (2) ◽  
pp. 251-254 ◽  
Author(s):  
Nicole Dion ◽  
Francis Minvielle
Keyword(s):  
Mating System ◽  
Tribolium Castaneum ◽  
Random Mating ◽  
Selection Response ◽  
Inbred Lines ◽  
Pupal Weight ◽  
Realized Heritability ◽  
Differential Selection ◽  
Selection For

Individual responses to selection for high pupal weight in Tribolium castaneum under two types of mating, cyclic full-sib random-mating system and random mating, were observed for 15 generations. No significant differences have been observed between the two types of mating for the selection response, differential selection, realized heritability, and the number of larvae per generation. Realized heritability of the pupal weight was 0.33 ± 0.02 and 0.42 ± 0.02 for the inbred lines and for the random-mated lines, respectively.Key words: inbreeding, pupa weight, Tribolium.

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