rome and Glucosephosphate-Dehydrogenase-Deficiency

Cyclic seasonal variation of genotype-specific fertility could interact with endemic diseases characterized by seasonal variation of severity resulting in changes of gene frequencies in the course of generations. Assuming that a given allele A has a frequency pw in infants conceived in the cold season and a frequency of ps in those conceived in the warm season and assuming that general fertility is the same in the two seasonal periods, the gene frequency in the population is pm = (pw + ps)/2; this frequency remains constant over the course of generations. The introduction of an endemic disease bearing negatively on general fertility and characterized by a seasonal pattern of severity could result in variations of the A allele frequency. If the maximum of endemicity coincides with the maximum value of the allele A frequency, the frequency of allele A will progressively decrease. A simple mathematical algorithm has been applied to two polymorphic enzymes (ACP1 and G6PD) correlated with past malarial morbidity in Sardinia and the Po River delta. The two systems show differences in gene frequency in relation to season of conception. The theoretical changes fit quite well with the data observed in Sardinian and Po delta populations, thus suggesting a mechanism that is an alternative to or concurrent with the classical mechanism that assumes a direct connection between the genetic systems and the biology of the malarial parasite.

Topics: Adaptation, Physiological; Algorithms; Alleles; Endemic Diseases; Female; Fertility; Fertilization; Gene Frequency; Genetic Variation; Geography; Glucosephosphate Dehydrogenase; Glucosephosphate Dehydrogenase Deficiency; Humans; Infant, Newborn; Isoenzymes; Italy; Malaria; Male; Phenotype; Pregnancy; Protein Tyrosine Phosphatases; Proto-Oncogene Proteins; Rome; Seasons; Time Factors

The frequency of carriers of the P(a)and P(c) alleles of the gene for acid phosphatase in the erythrocyte is significantly higher in male subjects deficient in glucose-6-phosphate dehydrogenase and having hemolytic clinical favism than it is in the general population. This observation seems to indicate that alleles (P(a) and P(c)) of a gene polymorphic in all human populations affect the fitness of the involved phenotypes in special genotypic and nongenotypic conditions.

Topics: Acid Phosphatase; Alleles; Erythrocytes; Ethnicity; Favism; Female; Gene Frequency; Glucosephosphate Dehydrogenase Deficiency; Humans; Male; Mediterranean Islands; Molecular Biology; Phenotype; Polymorphism, Genetic; Rome