Theoretical analysis of lethal factors in plant populations.

In this article, we are interested in the problem of the existence of a few linkage groups in which lethal infertile genes associated with yield factors are present. This hypothesis is supported by the finding of natural balanced lethal systems, which keep a short heterotic chromosome segment. It is very important to predict the number of generations that a balanced lethal system maintains in its linkage, in order to get a permanent heterozygosis without any problem with recombination.

The adenine and thymine molecules. Some excited singlet and triplet levels of the normal and tautomeric forms.

The shape of the barrier for the H transfer between the normal and tautomeric forms have been determined for the adenine and thymine molecules. The correlations for several singlet and triplet states has been calculated using the CNDO/2-CI method. The relative stability between both conformations and the agreement with some experimental values is also discussed.