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971.
Hideki Ueno 《Population Ecology》1994,36(1):121-124
Heritabilities and genetic correlations for body size characters and development period in a coccinellid beetle,Harmonia axyridis were estimated by a sib-analysis experiment. Positive genetic correlations were detected between size characters and development rate. If this is upheld in the field, genetic variation would be eliminated, as the loci affecting the characters are supposed to be fixed. However, the results indicated moderate heritabilities for all characters. Possible explanations for the results are discussed. 相似文献
972.
973.
Heritability of life span in mice and its implication for direct and indirect selection for longevity 总被引:1,自引:0,他引:1
S. Klebanov K. Flurkey T.H. Roderick J.R. Archer M.C. Astle J. Chen D.E. Harrison 《Genetica》2000,110(3):209-218
We found high narrow-sense heritability of life span based on the regression of offspring on average parental (midparent)
life spans. In two mouse populations prepared using the 4-way-cross design, mean ± SE heritabilities were 62 ± 11% (P ≤ 0.001) and 44 ± 15% (P ≤ 0.01). To reflect inherited rates of aging, rather than resistance to early disease, data from the first 25% to die were
deleted, so that only about 40% of families were used for offspring-midparent regressions. Heritabilities still remained high,
38% and 55%, for the same two populations, respectively. Populations studied in two other experiments did not show nearly
as high heritabilities; in one case probably due to environmental stress, and in the other probably because the strains used
did not have sufficient additive variance in genes regulating longevity. Significant heritabilities occurred only when a wild
derived inbred strain was included in the 4-way cross. The age when a female ceased to reproduce appeared to be related to
the life spans of her offspring, but only weakly, not approaching significance for any individual experiment. The age when
a female became infertile was related to her life span, but the relationship disappeared when short-lived mice were excluded
from the analysis. Our findings indicate that, in sufficiently diverse mouse populations, selection for increased longevity
should be possible and that the direct selection for parental life span will be a more efficient strategy than selection for
female reproductive life span.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
974.
Abstract We studied the evolutionary response to novel environments by applying artificial selection for total progeny biomass in populations of Drosophila melanogaster maintained at three different larval population densities. We found the relative amount of genetic variability for characters related with biomass to be lower and the correlation between them more negative at the intermediate density, and that selection resulted in changes in phenotypic plasticity and in patterns of resource allocation between traits. We found some evidence for tradeoffs between densities, which suggests that populations living at heterogeneous densities might be subject to disruptive selection. Our results show that adaptation to new environments may be a complex process, involving not only changes in trait means, but also in correlations between traits and between environments. 相似文献
975.
Cowpea genotypes (101) of diverse origin were evaluated for their endomycorrhizal colonization under natural field conditions in an alfisol soil. There was considerable variation in colonization ranging from 0 to 28.6%. The genetic coefficient of variability was high (55.9), heritability moderate (46.2) with high genetic advance (78.3) revealing that mycorrhizal colonization is not only host dependent but heritable. 相似文献
976.