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Biomedical subjects

A Camussi

Publications and source records attributed to A Camussi.

4 recordsLinked to original sources
PubMed1991

An APL procedure to estimate genotype by environment interaction when two environments are considered.

Genotype by environment interaction (GEI) is a relevant topic in many fields of applied biology. Normal parametric approaches following analysis of variance are not suitable when large differences between error variances within environments are present. We illustrate an APL program following Yamada's approach to estimate GEIs and ancillary statistics when two environments are considered. The choice of APL environment is based on its value as a useful tool in algorithm implementation and problem-solving. Its use is suggested in biological applications where matrix algebra is involved and an understanding of the computing complexity of problems is generally not required.

Algorithms↗
PubMed1988

Genetics: quantitative versus qualitative characters.

Some of the main topics regarding the inheritance of a complex trait are discussed and the relative procedure of genetic analysis described. In particular, two complementary approaches to the study of an inherited trait in humans are outlined: the biometrical approach and the proposed methodology of dissection of the complex trait into its components. Some aspects relating to the genetics of essential hypertension are used as examples.

Blood Pressure↗
PubMed1985

Genetic distances based on quantitative traits.

Morphological data showing continuous distributions, polygenically controlled, may be particularly useful in intergroup classification below the species level; an appropriate distance analysis based on these traits is an important tool in evolutionary biology and in plant and animal breeding.--The interpretation of morphological distances in genetic terms is not easy because simple phenotypic data may lead to biased estimates of genetic distances. Convenient estimates can be obtained whenever it is possible to breed populations according to a suitable crossing design and to derive information from genetic parameters.--A general method for determining genetic distances is proposed. The procedure of multivariate analysis of variance is extended to estimate appropriate genetic parameters (genetic effects). Not only are optimal statistical estimates of parameters obtained but also the procedure allows the measurement of genetic distances between populations as linear functions of the estimated parameters, providing an appropriate distance matrix that can be defined in terms of these parameters. The use of the T2 statistic, defined in terms of the vector of contrasts specifying the distance, permits the testing of the significance of any distance between any pair of populations that may be of interest from a genetic point of view.--A numerical example from maize diallel data is reported in order to illustrate the procedure. In particular, heterosis effects are used as the basis for estimates of genetic divergence between populations.

Analysis of Variance↗