Prospects and Pitfalls: Next-Generation Tools to Control Mosquito-Transmitted Disease

Mosquito-transmitted diseases, including malaria and dengue, are a major threat to human health around the globe, affecting millions each year. A diverse array of next-generation tools has been designed to eliminate mosquito populations or to replace them with mosquitoes that are less capable of transmitting key pathogens. Many of these new approaches have been built on recent advances in CRISPR/Cas9-based genome editing. These initiatives have driven the development of pathogen-resistant lines, new genetics-based sexing methods, and new methods of driving desirable genetic traits into mosquito populations. Many other emerging tools involve microorganisms, including two strategies involving Wolbachia that are achieving great success in the field. At the same time, other mosquito-associated bacteria, fungi, and even viruses represent untapped sources of new mosquitocidal or antipathogen compounds. Although there are still hurdles to be overcome, the prospect that such approaches will reduce the impact of these diseases is highly encouraging.

New genetic data on Amerindians from the Paraguayan Chaco

New data on 17 blood group and protein genetic systems obtained among the Ayoreo and Lengua Indians of Paraguay are presented. They include the first report on the red cell band-3 protein investigated among South American Indians. This information was integrated with previous results available for these two and four other groups. Five of the six populations reside in the Chaco area, while the sixth was included as an outgroup living elsewhere in Paraguay. Four of the five Chaco tribes exhibit good genetic homogeneity, but the Ayoreo are somewhat different. The results confirm the Chaco as a distinct biological (as well as cultural and economic) region, which should be considered in evaluations of genetic variability among South American Indians.

Genetic relationships between Amerindian populations of Argentina

A total of 495 individuals from five different Argentinian tribes was examined for variation in 23 blood group and protein genetic systems, and the results were integrated with previous data on some of these systems. These tribes generally present RH * R1, PGM1 * 1, and ACP * A frequencies lower and RH * R2, ESD * 1, and GLO * 1 prevalences higher than those observed in other South American Indian groups. Earlier studies with mitochondrial DNA showed that haplogroup A was present in low frequencies in these tribes, but haplogroup B showed a high prevalence among the Mataco. Average heterozygosities are very similar in the five tribes, while estimates of non-Indian ancestry are generally low. Both the blood group and protein, as well as the mtDNA data sets, divide the five tribes into two groups, and the relationships obtained with the blood group and protein systems are exactly those expected on the basis of geography and language. However, the topology obtained with the mtDNA results was different, possibly due to sampling effects or diverse patterns of exchange between the groups related to sex.

Genetic polymorphism of red cell membrane band 3 in Japanese Brazilians

Limited proteolysis of intact red cells has been shown to yield peptides of 60 kDa and, in some individuals, 63 kDa, from the band-3 membrane protein. In a random population sample of 117 Brazilians of Japanese origin, the allele frequencies of the band-3 variants were p60 = 0.889 +/- 0.0205 and p63 = 0.111 +/- 0.0205. The phenotype frequencies fit the Hardy-Weinberg equilibrium for the hypothesis of three phenotypes controlled by two codominant alleles of a single autosomal locus. The frequencies of the alleles in this population of Japanese ancestry are highly different from those of Brazilian Caucasoid blood donors but rather similar to those of Brazilian Negroid donors.

The 60 and 63 kDa proteolytic peptides of the red cell membrane band-3 protein: their prevalence in human and non-human primates

Three phenotypes based on the polymorphism of band-3 protein from human red cells are described. Limited proteolysis of intact red cells from most individuals (homozygotes) yields a peptide of 60 kDa, but in some cases (heterozygotes), there is also a 63-kDa peptide, and rarely only the single peptide of 63 kDa is found. This is the first description of the 63-kDa homozygote. The interpretation that the three phenotypes are controlled by two alleles of a single autosomal locus, with no dominance, is supported by population and family studies. The frequencies of the allele, which we designate as p63, is 0.041 +/- 0.0068 in Caucasoids and 0.125 +/- 0.0121 in Negroids. The electrophoretic profiles and molecular weights of the peptides obtained with several commercial proteases from Streptomyces griseus are similar to those obtained with chymotrypsin. Whereas band-3 protein in two New-World monkeys (Saimiri and Cebus) resisted pronase attack, an Old-World monkey (Macaca mulatta) was monomorphic for a 63-kDa fragment, and in an ape (Pan troglodytes), a doublet of 62 kDa and 64 kDa was found. Band-3 protein polymorphism appears to be a good marker for genetic differentiation in human populations.