Intl. J. of Mol. Evol. and Biodivers. 2015, Vol. 5, No. 1, 1-5
3
1.3 Data analysis
Powermarker (Liu and Muse, 2005) software was
used for the analysis of genotypic data to derive allele
and genotypic frequencies, genetic distances among
the individuals and to generate the phenetic tree.
2 Results
A total of 21 alleles were scored in the population at
the 07 microsatellite marker loci with a mean value of
03 alleles per locus (Table 3). Out of them 04 alleles
representing 04 markers were specific to SLT control
palm. The 21 alleles formed a total of 22 genotypes
ranging from 2 to 5 genotypes per marker and a mean
value of 3.1429 with 04 genotypes specific to SLT.
Markers CAC8, CAC65 and CNZ12 formed the highest
number of alleles, (4 alleles each) and the highest
number of phenotypes also (5, 4 and 4 respectively).
Table 3 Summary statistics of genotypic data
Marker
No of alleles
No of genotypes
Gene diversity Heterozygosity
PIC
CAC8
CAC20
CAC23
CAC65
CNZ12
CNZ40
CNZ44
Total
Mean
4 (A1- A4)
2 (B1- B2)
2 (C1 - C2)
4 (D1 - D4)
4 (E1 - E4)
2 (F1 - F2)
3 (G1- G3)
21
3
5
2
2
4
4
2
3
22
3.1429
0.2688
0.0713
0.1975
0.6693
0.4896
0.0713
0.4170
-
0.3121
0.1
0.0
0.0
0.125
0.0833
0.0
0.0
-
0.044
0.2561
0.0688
0.1780
0.6066
0.4305
0.0688
0.3788
-
0.2839
As reported in table 03 gene diversity values ranging
from a minimum of 0.0713 at CAC20 and CNZ40 to a
maximum of 0.6693 at the marker locus CAC65 were
recorded with a mean value of 0.3121. CAC65
recorded the highest number of heterozygotes while
four markers scored zero heterozygotes recording a
mean value of only 0.044 among the observed
individuals.
2.1 DNA fingerprints for the Sri Lanka Yellow
Dwarf population
The single SLT palm scored alleles which were
different to the SLYD population as expected at 04 of
the marker loci. However, although naturally
cross-pollinating and therefore expected to be highly
heterozygous, SLT recorded homozygous alleles at all
the marker loci examined in this study. This supports
earlier findings for the comparatively low
heterozygosity of Sri Lanka tall coconuts (Ekanayake,
2010). On the other hand although expected to be
homozygous due to naturally self-pollinating nature,
resulting in pure-lines, SLYD recorded a total of 05
heterozygous individuals at 07 different marker loci.
The second comparative coconut form Sri Lanka Green
Dwarf (SLGD) scored identical alleles with the dwarf
like SLYD (DL-SLYD) except at marker locus CAC65.
Consequently, SLGD and DL-SLYD could be
differentiated at the CAC65 marker locus where SLGD
scored homozygous D1 alleles while DL-SLYD scored
mainly D3 alleles. Microsatellite marker CAC65 could
also be used to differentiate the DL-SLYD from the tall
like group within the SLYD (TL-SLYD) (Table 4).
TL-SLYD recorded a higher frequency of D1 followed
by D2 alleles while DL-SLYD recorded a higher allelic
frequency of D3. The results also display a higher
allelic variation of TL-SLYD at the marker locus
CAC65 compared to DL-SLYD.
Table 4 Allele frequencies at marker locus CAC65
Allele
Frequency in SLYD
Frequency within DL-SLYD
Frequency within TL-SLYD
D1
D2
D3
D4
34.091
13.636
45.454
6.818
10.0%
0%
80.0%
10.0%
54.167%
25.0%
16.667%
4.167%
