![]() Recently, the increased focus on the genetics of adaptive variation in natural populations have renewed the interest in allozyme loci, as these may serve as a good starting point for detecting genomic regions under selection (Wheat et al. 1991) and other methods for detecting changes in the DNA sequence itself became more efficient. 1977), STR genotyping (Tautz 1989 Schlotterer et al. Allozyme analysis was the primary method to collect population genetic data (Hubby and Lewontin 1966 Lewontin and Hubby 1966) but was largely replaced when dideoxy-terminator nucleotide sequencing (Sanger et al. Such expressed genetic variation is more likely to be subject to local selection and consequently detected as outliers in comparisons with selectively neutral DNA sequences, such as the mitochondrial control region or single tandem repeat (STR) loci (Ford 2002 Storz and Nachman 2003 Canino et al. 2010 Hoffmann and Sgro 2011).Īllozymes are different variants of enzymes coded by the same locus (Hunter and Markert 1957 Ingram 1957 Markert and Moller 1959 Crick et al. 2012), which in turn may warrant additional protective measures (Nielsen et al. Divergent selection might be due to unique local adaptations (Protas et al. ![]() Such signatures are usually inferred as loci subject to either divergent or balancing selection, respectively (Tajima 1989 McDonald and Kreitman 1991 Fu and Li 1993 Kreitman 2000). The effects of migration are typically genomewide however, at occasion, some loci may appear as outliers displaying a substantially higher or lower degree of genetic divergence relative to the genomewide level of genetic divergence. This specific aspect has been utilized extensively to guide the management of natural populations where a significant level of population genetic divergence serves as the basis for delineating a species into conservation and management units (Moritz 1994 Waples and Gaggiotti 2006 Palsbøll et al. The appeal of genetic inference methods to assess population genetic structure is grounded in the correlation between the genetic similarity and gene flow among populations. ![]() Population genetic data have been utilized to infer intraspecific population genetic structure in ecology and conservation since the early 1960s when the advent of experimental methods enabled detection of individual genetic variation (Sick 1961). As for North Atlantic fin whale population structure, our findings support the low levels of differentiation found in previous analyses of DNA nucleotide loci. While such plasticity is intriguing in itself, and of fundamental evolutionary interest, our key finding is that the observed allozyme variation does not appear to be a result of genetic drift, migration, or selection on the MDH-1 and MPI exons themselves, stressing the importance of interpreting allozyme data with caution. Following extensive error checking and analysis of additional bioinformatic and morphological data, we hypothesize that the observed allozyme polymorphisms may reflect phenotypic plasticity at the cellular level, perhaps as a response to nutritional stress. We sequenced the exons encoding for the two most divergent allozyme loci ( MDH-1 and MPI) and failed to detect any nonsynonymous substitutions. Here, we report the results of an investigation into the molecular basis of the substantial degree of genetic divergence previously reported at allozyme loci among North Atlantic fin whale ( Balaenoptera physalus) populations. Consequently, substantial efforts have been directed toward such outlying loci in order to identify traits subject to local adaptation. Above average population, genetic divergence may be due to divergent selection as a result of local adaptation. Effects of such gene flow are typically genomewide however, some loci may appear as outliers, displaying above or below average genetic divergence relative to the genomewide level. ![]() The appeal of genetic inference methods to assess population genetic structure and guide management efforts is grounded in the correlation between the genetic similarity and gene flow among populations. ![]()
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