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1993
Fellow
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Beatriz
Alicia García, Ph.D.
Universidad Nacional de Córdoba
Cátedra de Bioquímica y Biología Molecular
Facultad de Ciencias Médicas
Pabellón Argentina 2do Piso
Ciudad Universitaria
5000 Córdoba
Argentina
Tel: (54)(351) 433-3024
Fax: (54) (351) 433-3072
E-mail: bgarcia@biomed.uncor.edu
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Country:
ARGENTINA
Field:
Genetics
Research Interest:
Most of the 129 species recognized for
Triatominae have been reported to be either naturally or experimentally
infected with T. cruzi. However, only a few are considered as effective
vectors of Chagas' disease in humans because of their high degree of adaptation
to the domestic environments and anthropophily. Although some species
are more efficient vectors than others, it is important to consider species
which may replace the principal T. cruzi transmitters when they have been
eradicated by control measures. In fact, sylvatic species have been known
to replace domestic vectors after their elimination. The knowledge of
the relationships and evolutionary history of different Triatominae species
is, therefore, of considerable importance. Our interest is to understand
the phylogenetic relationships of species of Triatominae using DNA sequence
data. With this purpose we have sequenced mitochondrial DNA fragments
of 12S and 16S ribosomal RNA genes in thirty two species of this subfamily,
and cytochrome oxidase I protein coding gene in nine.
On the other hand, Triatoma infestans is the main vector of T. cruzi in
South America between the latitudes of 10° and 46° S. Until now
the interruption of transmission of T. cruzi consists in the elimination
of vector populations by insecticide treatment of infested dwellings;
however, the continuation of the control interventions is a new challenge
for the Southern Cone of Latin America. The long-term effectiveness of
the control campaigns is dependent upon the knowledge of the vector population
structure. Modern molecular approaches, employing DNA technology, have
introduced vast new possibilities for such studies. In this regard, it
is necessary to study the genetic population structure, levels of population
differentiation, and genetic exchange in natural populations of T. infestans.
Since genetic exchange among populations is related to migration, estimation
of gene flow affords valuable information to assess the possibility of
expansion of Chagas transmitters. Besides, the genetic analysis of vector
populations may be useful in entomological surveillance of Chagas vectors
control programs, since it may provide information on the nature of the
source of the insects in re-colonized areas and also to establish a new
way to survey the population dynamics of these blood-sucking insects.
Among the new DNA-based methods, microsatellites have permitted greater
resolution of genetic variation of populations. They are one of the most
powerful molecular markers for estimating genetic parameters and describing
population genetic structure and gene flow. Until now, microsatellite
primers have not been developed for T. infestans. With the purpose to
detect genetic changes related to the insecticide application impact and
/ or possible T. infestans recolonization patterns, which are influencing
control efficiency, we will estimate the degree of genetic intra- and
interpopulation variability and the level of genetic flow in natural populations
of this species, using microsatellite DNA markers. In order to reach these
objectives, firstly we are working with the purpose to isolate microsatellite
loci from T. infestans and develop a new set of primers for amplification
of these DNA segments in this species.
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