Birth Weight and Gestation Time in Relation to Maternal Age, Parity and Infant Survival

Karn, Mary N.; Penrose, L. S.

doi:10.1111/j.1469-1809.1951.tb02469.x

Cited by 371 publications

(206 citation statements)

References 6 publications

Supporting

Mentioning

187

Contrasting

Unclassified

Order By: Relevance

“…A clear example of stabilising selection operating on growth rate comes from the classic work of Karn andPenrose (1951, see also Gordon, 1977) on human birth weight: newborn infants of intermediate birth weights had higher viabilities than those of more extreme weights. Since, in man at least, birth weight is more dependent on maternal genotype and maternal environment than on foetal genotype (which contributes about 24 per cent of birth weight variance, Robson, 1978), it is likely to be a poor character to use in man (and probably other mammals) in searches for heterozygosity/growth rate correlations.…”

Section: Discussionmentioning

confidence: 99%

Growth rate and heterozygosity in the plaice, Pleuronectes platessa

1986

View full text Add to dashboard Cite

Samples of young plaice were examined to see if there was any relationship between growth rate and individual heterozygosity, screened across five polymorphic enzyme loci (Pgm-1, Ada, Mdh-2, Pgi-2, aGpdh-1). Two out of 46 samples showed a significant negative correlation between growth rate and multi-locus heterozygosity; none showed a significant positive correlation. There was no overall tendency to negative or positive correlations. The largest sample (N = 689) showed no relationship between multi-locus heterozygosity and growth rate, although one of the five loci, aGpdh-1, showed a significant positive correlation. The only significant correlation in the next largest sample (N = 248) was between multi-locus heterozygosity and growth rate, and that was negative. Fish of intermediate growth rate were not significantly different in heterozygosity from faster or slower growing fish. There was no relationship between variability in growth rate and multi-locus heterozygosity. These findings are discussed in the context of similar surveys from other species, and the conclusion drawn that the universality of a positive relationship between growth rate and multi-locus heterozygosity remains to be established.

show abstract

Section: Discussionmentioning

confidence: 99%

Growth rate and heterozygosity in the plaice, Pleuronectes platessa

1986

View full text Add to dashboard Cite

show abstract

“…Its consequences are more often maintenance of the status quo than systematic changes in gene frequencies. There is evidence that the modal phenotypes in a population have the highest reproductive fitness (Rendel, 1943;Karn and Penrose, 1951;Jayant, 1966). The optimum phenotype itself changes with shifts in gene frequency or in the environment and it is assumed that the modal phenotype is a result of natural selection.…”

Section: Introductionmentioning

confidence: 99%

Stabilising selection in constant and fluctuating environments

Gibson

Bradley

1974

Heredity

View full text Add to dashboard Cite

SUMMARYSelection in both constant and fluctuating temperature environments for a constant bristle number in Drosophila melanogaster resulted in the maintenance of that number and in a decrease of both genetic and environmental variance. Although mean bristle number in the control lines increased over the early generations there was a significant net decrease. Phenotypic variance decreased significantly, especially in later generations. In both control lines and in the line selected at 20-29° C. there was a significant decrease in asymmetry of bristle number. There was also a decrease in environmental variance in these three lines. Transplant experiments showed that when the lines were cultured in alien environments phenotypic variance tended to increase in the fluctuating and decrease in the constant temperature environment. However at generation 39, the phenotypic variance of lines selected in the fluctuating environment increased when samples of the lines were cultured in the constant temperature environment. The results indicate that stabilising selection can be effective in both fluctuating and constant temperature environments.

show abstract

“…However, in these cases little is known about the genetic control of the character. Birth weight in man has been shown to have a central optimum value (Karn and Penrose, 1951 ;Jayant, 1966). Thoday (1958) has argued that sternopleural chaeta number in Drosophila rnelanogaster is a character of adaptive significance as it is affected by natural selection.…”

Section: Introductionmentioning

confidence: 99%

Stabilising selection in Drosophila melanogaster

Barnes¹

1968

Heredity

View full text Add to dashboard Cite

Birth Weight and Gestation Time in Relation to Maternal Age, Parity and Infant Survival

Cited by 371 publications

References 6 publications

Growth rate and heterozygosity in the plaice, Pleuronectes platessa

Growth rate and heterozygosity in the plaice, Pleuronectes platessa

Stabilising selection in constant and fluctuating environments

Stabilising selection in Drosophila melanogaster

Contact Info

Product

Resources

About