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L Gedda

Publications and source records attributed to L Gedda.

At least 19 recordsLinked to original sources
PubMed1990

A stochastic model of the genetic predisposition to ageing: an application to twin data.

In previous papers a stochastic model of the ageing process has been proposed. Some genetic parameters (redundance, repair) have been used to explain the observed differential predisposition to the process and family heredity. Because the process is basically due to effective random mutations, any individual of the population would be predisposed differently to ageing according to the structure of his/her genome. In the present paper, the previous model is generalized to take into account an additional genetic parameter, namely, the stability against random mutations, defined as the probability that a random mutation in a codon would produce no mutation in the corresponding protein. Estimation problems connected with the model are approached on the basis of twin data in maximum likelihood estimation as well as in bayesian framework. Some comparisons between the two methods are reported.

Aging↗
PubMed1979

Sleep and dream characteristics in twins.

A study of sleep and dream characteristics has been carried out by questionnaire on a sample of 77 MZ and 76 DZ same-sex twin pairs of two age groups, 6-8 and 16-18 years. Genetic effects could not be detected in the younger age group and appeared to be rather limited in the older one, possibly as a result of the limited variability of the considered variables and of the levelling influence of the common environment.

Adolescent↗
PubMed1979

Twin azygotic test for the study of hereditary qualitative traits in twin populations.

Following previous formulations of a model of qualitative analysis of twin population data independent of zygosity, a new Bayesian approach has been developed. The present model can be applied to any qualitative genetic trait in twin population data, provided no specific source of variation be introduced by the twin condition, and allows not only estimation of the frequencies of mono- and dizygosity as well as the gene frequencies, but also verification of the trait's mode of inheritance.

Bayes Theorem↗
PubMed1978

The role of chronogenetics and of gemellology in the prevention of genetic morbidity.

The prevention of hereditary diseases after birth is essentially based on the detection of these diseases at their preclinical level. This may be made possible through a careful pedigree examination and possible identification of a "genealogical alarm", as well as a detailed clinical examination of the subject and possible identification of preclinical signs of the pathogenesis, i.e., of a "clinical alarm". The respective roles of chronogenetics and of gemellology in this approach are reviewed.

Female↗
PubMed1978

A hundred years of gemellology.

Over the past hundred years, since Sir Francis Galton first pointed out its scientific value, the study of twins has considerably widened its scope and significance. Gemellology has come to represent an important branch of human genetics and to be applied to the most diverse fields of biomedical and behavioral research, besides obviously contributing to the study of the specific biological, medical, and psychological aspects of the twin condition. More recently, then, it has in turn originated a new branch of modern genetic research, chronogenetics. Finally, sponsored and coordinated by the Mendel Institute in Rome, an International Society for Twins Studies has developed.

Female↗