Preliminary Microsatellite Data for the Western Mosquitofish, Gambusia affinis

Seven polymorphic microsatellite loci, Gafm 1-7, have been reported for Gambusia affinis (Spencer et al 1999, 2000), and three loci, Mf 1, 6 & 13, have been reported for the eastern mosquitofish, Gambusia holbrooki  (Zane et al 1999). We have purchased primers for all 10 loci, and thus far have optimized 6 of them: Gafm 2, 3, 4, 5, 6 & 7, and have run a preliminary survey of 20 fish collected from one net haul, within one small pool, within a stream that supports a large population of mosquitofish. This sample contained several juveniles, which may be from a family group.

 

Locus N Expected Size Size Range Temp [Mg] mM Alleles Ho He N Size Range* Temp* [Mg] mM Alleles* Ho* He*
Gafm1 20

107

105-107

52

1.5

 2

0.18

0.16

 -  -  -  - -  -  -
Gafm2 20

147

125-210

65

1.5

21

0.71

0.80

18

~155-165

58

2

2

0.40

0.44

Gafm3 20

262

229-280

65

1.5

19

0.75

0.93

19

~245-280

56

2

3

0.65

0.58

Gafm4 20

218

171-259

65

1.5

21

0.60

0.95

20

~188-200

62

2

4

0.45

0.49

Gafm5 20

264

243-291

52

1.5

10

0.90

0.81

 8

 

56

2

3

0.60

 0.52
Gafm6 20

196

178-202

65

1.5

 8

0.75

0.76

18

~195

56

2

1

0.00

0.00

Gafm7 20

188

162-197

65

1.5

20

0.95

0.91

20

~170-180

59

2

4

0.75

0.60

Table 1. The original description of the Gafμ loci (in black, Spencer et al. 1999), and my preliminary survey of these loci for 20 fish in my population (in blue). Scans of the gels from which these data were taken appear below. Ho: observed heterozygosity; He: expected heterozygosity based on Hardy-Weinberg; [Mg]: magnesium concentration in mM; Temp: annealing temperature; sizes are in bp. 

Gafμ allele fragment lengths in the source population (Spencer)

We are in the process of optimizing the remaining Gafm locus, and the three Mf loci. Once that is finished, we will survey allelic variation within and among populations.

 

 

 

 

 

Spencer, CC, Chlan, CA, Neigel, JE, Scribner, KT, Wooten, MC & Leberg, PL 1999. Polymorphic microsatellite markers in the western mosquitofish, Gambusia affinis. Mol Ecol 8:157-158.(link)

Spencer, CC, Neigel, JE & Leberg, PL 2000. Experimental evaluation of the usefulness of microsatellite DNA for detecting demographic bottlenecks. Mol Ecol 9:1517-1528. (link)

Zane, L, Nelson, WS, Jones, AG & Avise, JC 1999. Microsatellite assessment of multiple paternity in natural populations of the live-bearing fish, Gambusia holbrooki. J Evol Biol 12:61- 69. (link)