Two enzymatic systems (esterase and esterase-D), analysed by using the starch gel electrophoresis technique on plant young leaves cultivated in the higher land (terra firme), from seeds of camu-camu, Myrciaria dubia (Kunth) McVaugh-Myrtaceae obtained from three natural population samples (Iquitos, Boa Vista and Uatumã), revealed 6 loci: Est-1, Est-2, Est-3, Est-4, Est-D1 and Est-D2. Two of the six gene loci presently examined (Est-3 and Est-D2) showed to be polymorphic, so they happen to be valuable for characterizing the species population structure. The polymorphism patterns shown in the Est-3 and Est-D2 loci of camu-camu, are typical of monomeric and dimeric enzymes, respectively. The locus Est-3 showed a huge genetic imbalance within and among the population samples examined, due to an excessive observed numbers of heterozygote plants compared to their expected numbers. The locus Est-D2 showed an exclusive polymorphism for the alleles Est-D2¹, Est-D2² and Est-D2³, and a good genetic balance in the Uatumã population sample. On account of that, among all gene loci investigated here, Est-D2 seems to be the most suitable locus for identifying and delimiting camu-camu probable stocks. Hence, this locus has to be present in the list of the isoenzymatic markers for future research on the species population genetics in the Amazon region. Data on allelic frequency distribution, genetic distance and genetic variation estimates on the 6 esterase loci investigated, were effective for demonstrating genetic differences among the surveyed species population samples. The highest values of mean heterozigozity (0.1353); proportion of polimorphic loci (0.33) and average number of alleles per locus (1.33) revealed in the Uatumã population sample, are due to the presence of an extra polymorphic locus (Est-D2) when compared with other surveyed samples.
Camu-camu (Myrciaria dubia); population structure; esterases (esterase and esterase-D); isoenzymes