GENETIC CONTROL OF BODY TRAITS AND GROWTH PATTERN IN LEBISTES

1981 ◽  
Vol 23 (1) ◽  
pp. 141-149 ◽  
Author(s):  
M. Luisa Vanelli ◽  
Carlo Pancaldi ◽  
Rita Alicchio ◽  
Domenico Palenzona
Keyword(s):  
Genetic Variability ◽  
Growth Rates ◽  
Growth Pattern ◽  
Inbred Lines ◽  
Environment Interaction ◽  
Genetical Analysis ◽  
Genetic Components ◽  
Genotype Environment Interaction ◽  
Metric Traits ◽  
Lebistes Reticulatus

Genetic variability and growth pattern of metric traits were studied in inbred lines of Lebistes reticulatus (Peters) obtained by crossing full sibs in three generations. Sub-sublines with different growth rates of body length and body weight were identified; on the whole inbred population a genetical analysis was performed for both traits at different ages on raw data and on data adjusted for growth rate regression. Both analyses reveal the presence of a great amount of genotype—environment interaction and of a certain amount of genetic variation for body traits. The differences concerning the genetic components of variation observed in the two analyses within each population indicate an influence of the different growth rates of sub-sublines on the detection of genetic variability.

Genotype—environment interaction III. Interactions in Drosophila melanogaster

1975 ◽  
Vol 191 (1104) ◽  
pp. 387-411 ◽  
Keyword(s):  
Environmental Change ◽  
Total Yield ◽  
Inbred Lines ◽  
Environment Interaction ◽  
Substitution Lines ◽  
Genotype Environment Interaction ◽  
True Breeding ◽  
Chromosome Ii ◽  
Response To Environmental Change ◽  
Culture Container

The responses of two characters, number of sternopleural chaetae and total yield of offspring (which depends on the mother’s genotype), to change in the temperature at which the flies were raised and type of culture container in which they bred were followed in the two inbred lines, Wellington (Well) and Samarkand (Sam). In respect of chaeta number Well was more sensitive to change of the environment than Sam, which furthermore responded in the opposite direction to Well. In respect of yield of offspring the two lines responded similarly. The genetic control of these responses to environmental change was investigated by using the eight substitution lines which comprise all the possible true breeding combinations of the three major chromosomes (X, II and III) from Well and Sam. Two experiments were carried out, the first a diallel experiment at three temperatures (18, 21.5 and 25 °C), and the second an experiment in which the eight lines were raised in nine environments comprising all combinations of the three temperatures and three types of culture. Chaeta number changes more with temperature than with type of culture, whereas the reverse is true of yield of offspring. In respect of chaeta number the genes chiefly responsible for response to environmental change are borne on a different chromosome (II) than those chiefly responsible for variation in mean chaeta number (III), and there are indications of a similar situation in respect of yield of offspring. It is concluded that different characters are separately adjustable by selection in their responses to enviromental change, that sensitivity of a character to environmental change is adjustable separately from mean expression of the character, and that the detailed patterns of response to a range of environments (e. g. temperatures) are separable from the magnitude of the overall change induced by these environments.

GENOTYPE × ENVIRONMENT INTERACTIONS FOR POSTWEANING GROWTH PERFORMANCE OF BACKCROSS BULLS

1987 ◽  
Vol 67 (2) ◽  
pp. 359-370 ◽  
Author(s):  
G. W. RAHNEFELD ◽  
R. M. McKAY ◽  
H. T. FREDEEN ◽  
G. M. WEISS ◽  
J. A. NEWMAN ◽  
...  
Keyword(s):  
Growth Rates ◽  
Fixed Effects ◽  
Performance Test ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Environment Interaction ◽  
Test Results ◽  
Ge Interaction ◽  
Genotype Environment Interaction ◽  
Daily Gain

The effects of pretest and genotype × environment (GE) interactions of 137 reciprocal backcross bulls produced under two contrasting environments (Brandon, Manitoba and Manyberries, Alberta) were evaluated for postweaning performance traits. Differences in weaning weight and average daily gain during the pretest periods defined as preweaning (ADGBW), weaning to on-test (ADGWT), and birth to on-test (ADGBT) associated with the fixed effects of station of origin, breed cross and station of origin by test were not significant. Station of test effects were significant (P = 0.0001) for ADGWT and ADGBT. None of the GE interactions involving the station of origin was significant (P > 0.10) for the postweaning growth traits and probabilities exceeded 0.20 for all but three of the 40 traits. The GE interactions involving station of test were nonsignificant (P > 0.20) for all but eight traits. All of these exceptions involved the cumulative average daily gain in the eight periods which excluded the first 14 d of test. Although the GE interaction for average daily gain for 140 d of test was not significant there were substantial breed cross differences in growth rates at the two test locations. Users of performance test results, however, are generally concerned with absolute performance values, not statistically significant differences. Viewed in this context, the differential responses of genotypes under different test environments, even though statistically nonsignificant, could have important implications to the industry. Key words: Cattle, postweaning growth, genotype × environment interaction

Genetic Epidemiology of Colorectal Cancer

1996 ◽  
Vol 82 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Silvano Presciuttini ◽  
Paolo Strigini
Keyword(s):  
Colorectal Cancer ◽  
Genetic Epidemiology ◽  
Segregation Analysis ◽  
Cancer Susceptibility ◽  
Familial Aggregation ◽  
Environment Interaction ◽  
Cancer Genetic ◽  
Genetic Components ◽  
Cancer Susceptibility Genes ◽  
Genotype Environment Interaction

Starting from a survey of the studies on familial aggregation of colorectal cancer, we introduce the aims of genetic epidemiology. One of its main goals is to assess population frequency of cancer susceptibility genes and to determine the age-specific risks for carriers with respect to non-carriers. In section two, segregation analysis investigations are reviewed, and inferences on the relevance of genetic components of susceptibility to colorectal cancer are drawn. In section three, the HNPCC paradigm is discussed in the light of the Knudson model of tumorigenesis and recent advances of molecular research. In the last section we show an example of genotype/environment interaction in the etiology of a particular cancer and present a conceptual framework for studies on cancer genetic epidemiology in terms of attributable and relative risk.

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