Concordance between dispersal and mitochondrial gene flow: isolation by distance in a tropical teleost, Lates calcarifer (Australian barramundi)

Abstract

Patterns of population subdivision and the relationship between gene flow and geographical distance in the tropical estuarine fish Lates calcarifer (Centropomidae) were investigated using mtDNA control region sequences. Sixty-three putative haplotypes were resolved from a total of 270 individuals from nine localities within three geographical regions spanning the north Australian coastline. Despite a continuous estuarine distribution throughout the sampled range, no haplotypes were shared among regions. However, within regions, common haplotypes were often shared among localities. Both sequence-based (average ST = 0.328) and haplotype-based (average ST = 0.182) population subdivision analyses indicated strong geographical structuring. Depending on the method of calculation, geographical distance explained either 79 per cent (sequence-based) or 23 per cent (haplotype-based) of the variation in mitochondrial gene flow. Such relationships suggest that genetic differentiation of L. calcarifer has been generated via isolation-by-distance, possibly in a stepping-stone fashion. This pattern of genetic structure is concordant with expectations based on the life history of L. calcarifer and direct studies of its dispersal patterns. Mitochondrial DNA variation, although generally in agreement with patterns of allozyme variation, detected population subdivision at smaller spatial scales. Our analysis of mtDNA variation in L. calcarifer confirms that population genetic models can detect population structure of not only evolutionary significance but also of demographic significance. Further, it demonstrates the power of inferring such structure from hypervariable markers, which correspond to small effective population sizes.

Mitochondrial genealogy of Western Australian barramundi: applications of inbreeding coefficients and coalescent analysis for separating temporal population processes

“…Australian barramundi populations (0·004-0·064) given by Shaklee & Salini (1985), Shaklee et al (1993) and Keenan (1994), but are similar to mtDNA sequence-based φ ST estimates for the same populations given by Chenoweth et al (1998a;0·328). These results may indicate that population subdivision is greater for mtDNA than for nuclear genes, which is a common empirical finding (Hallerman & Beckmann, 1988;Billington & Hebert, 1991;Nielsen et al, 1996;Chenoweth & Hughes, 1997).…”

“…Estimates of mtDNA variation (h and π) for barramundi were generally higher than those reported for a range of coastal and marine species including the catadromous eel Anguilla rostrata (Le Sueur) (see Table 2 in Avise, 1992), but are similar to values estimated by Chenoweth et al (1998a) for the mtDNA control region in Australian barramundi populations. The absence of mtDNA variation in the population from Cairns may be due to the small sample size, although Chenoweth et al (1988b) also reported low mtDNA diversity in eastern Australian populations of barramundi, possibly resulting from a population bottleneck during recent evolution.…”

Genetic population structure of mangrove jack, Lutjanus argentimaculatus (Forsskål)

“…Pleistocene, the wide continental shelf to Australia's north including the Torres Strait was exposed, making Papua New Guinea and Australia a single land mass (van Oosterzee 1997). This vicariant event is reflected in the population genetics of at least three tropical Australian fishes -the saddle-tail sea perch (Lutjanus malabaricus) (Elliott 1996); barramundi (Chenoweth et al 1998b) and Spanish mackerel (J. R. Ovenden, R. Street, R. C. Buckworth, C. Foschia and S. J. Newman, unpublished data) -and of green turtles (Norman et al 1994). The frequencies of the three most common RFLP (restriction fragment length polymorphism) haplotypes in sea perch mtDNA were 61, 15 and 12% in a sample from the Queensland east coast (near Townsville), Fig.…”

Population genetic structure of coral reef species Plectorhinchus flavomaculatus in South China Sea

“…Tropical Pacific sea urchins also show a pattern of isolation by distance, in which F ST measured with mitochondrial sequence data increases markedly with geographic distance between pairs of populations (Palumbi et al, 1997). Isolation by distance was also detected in Atlantic cod (Gadus morhua) and coral reef species Australian barramundi (Lates calcarifer) (Pogson et al, 2001;Chenoweth et al 1998).…”