NADP-dependent isocitrate dehydrogenase of Astyanax scabripinnis (Pisces, Characidae) from three altitudes at Grande Stream, Campos do Jordão, SP

Abstract

Electrokinetic, thermic, and kinetic properties of products of NADP-dependent isocitrate dehydrogenase (IDHP; EC 1.1.1.42) loci of Astyanax scabripinnis (Pisces, Characidae) collected at three different altitudes (700 m, 1,800 m, and 1,920 m) of Grande Stream at Campos do Jordão, State of São Paulo, Brazil, were analyzed. Two IDHP bidirectionally divergent loci, a single skeletal muscle, the IDHP-A*, and a single liver IDHP-B*, both polymorphic, were detected in the three different altitude populations. The variant allele *128 at the IDHP-A* locus, had its highest frequency detected in the 1,920 m population (0.494). Among the nine variant alleles detected at the IDHP-B* locus (*37, *57, *69, *79, *85, *114, *119, *124, and *140), the *37 and 79 were detected only in 1,800 m population. Chi-square values showed that only the 700 m population is not in Hardy-Weinberg equilibrium for the IDHP-A* locus, while for the IDHP-B* locus, no population is. Homogeneity Chi2 test indicated that the populations are significantly different in their A and B phenotype frequencies. Wright's FST mean value (0.036 and 0.32, IDHP-A* and IDHP-B*, respectively) was 0.178 for the three altitude populations which means that 82% of total genetic diversity was found among individuals of each one of the populations. Stability at environmental temperatures (16 degrees to 21 degrees C), and apparent Km and Vmax values of each A-phenotype skeletal muscle crude extract suggest different roles of A-isoforms during the increased lipogenesis that occurs in fish at low temperatures.

Constitutive Heterochromatin and Ag-NOR Polymorphisms in the Small Characid Fish Astyanax scabripinnis (Jenyns, 1842)

“…Probably the isolation among different flocks of A. scabripinnis on the same stream, produced by a topographic discontinuity is not complete, that is, gene flow may occur only in one direction, i.e., down stream. Other studies on enzyme polymorphisms also reinforce this hypothesis (Santos 2000, Munin et al 2004.…”

“…Possibly the gene flow occurs only downstream and the flowing up of this small characid to the headwater is rarely probable. This partial isolation can facilitate the development of different genetic patterns along ecological gradients on the same watercourse, at the cytogenetic and the enzymatic polymorphisms levels (Santos 2000, Munin et al 2004. The transposition events on chromosome telomeric portions, followed by tandem amplification, result in new cytotypes to be selected in the populations, and eventually into flocks located downstream.…”

A comparative structural cytogenetic study in three allopatric populations of Astyanax scabripinnis (Teleostei: Characidae)

“…In order to minimize problems of identification, unnatural inferences about the relationships, and wrong evolutionary series, each approach should take into account the local geomorphological history and biological characteristics of the species and their evolutionary time (ARTONI et al 2009). The great diversity in the karyotype macrostructure found in A. scabripinnis is considered a common trait of this species (MOREIRA-FILHO & BERTOLLO 1991) and molecular cytogenetic data have reinforced this observation (MOISÉS & ALMEIDA-TOLEDO 2002, MUNIN et al 2004, SOFIA et al 2006. Such diversity is very likely facilitated by the fact that this fish occupies river headwaters and probably became restricted to these environments (GOMES & AZEVEDO 1960, BRITSKI 1972.…”

Evaluation of Parkia pendula lectin mRNA differentially expressed in seedlings

“…The identification and isolation of eukaryotic genes differentially expressed in cell/tissues as a result of genetic, environmental and/or induced variation have been pursued by researchers in many areas of biology, such as developmental biology and plant physiology (Munin et al, 2004). Liang and Pardee (1992) introduced a powerful technique called differential display reverse transcription polymerase chain reaction (DDRT-PCR).…”