Limits...
Genetic diversity and differentiation among populations of the Indian eri silkworm, Samia cynthia ricini, revealed by ISSR markers.

Vijayan K, Anuradha HJ, Nair CV, Pradeep AR, Awasthi AK, Saratchandra B, Rahman SA, Singh KC, Chakraborti R, Urs SR - J. Insect Sci. (2006)

Bottom Line: Samia cynthia ricini (Lepidoptera: Saturniidae), the Indian eri silkworm, contributes significantly to the production of commercial silk and is widely distributed in the Brahmaputra river valley in North-Eastern India.The high G(ST) value (0.657) among the populations combined with low gene flow contributes significantly to the genetic differentiation among the S. cynthia ricini populations.Based on genetic diversity, these populations can be considered as different ecotypes and in situ conservation of them is recommended.

View Article: PubMed Central - PubMed

Affiliation: Seribiotech Research Laboratory, Central Silk Board, CSB Campus, Kodathi, Carmelram PO, Bangalore, Karnataka, India. kvijayan01@yahoo.com

ABSTRACT
Samia cynthia ricini (Lepidoptera: Saturniidae), the Indian eri silkworm, contributes significantly to the production of commercial silk and is widely distributed in the Brahmaputra river valley in North-Eastern India. Due to over exploitation coupled with rapid deforestation, most of the natural populations of S. cynthia ricini are dwindling rapidly and its preservation has become an important goal. Assessment of the genetic structure of each population is a prerequisite for a sustainable conservation program. DNA fingerprinting to detect genetic variation has been used in different insect species not only between populations, but also between individuals within a population. Since, information on the genetic basis of phenotypic variability and genetic diversity within the S. cynthia ricini populations is scanty, inter simple sequence repeat (ISSR) system was used to assess genetic diversity and differentiation among six commercially exploited S. cynthia ricini populations. Twenty ISSR primers produced 87% of inter population variability among the six populations. Genetic distance was lowest between the populations Khanapara (E5) and Mendipathar (E6) (0.0654) and highest between Dhanubhanga (E4) and Titabar (E3) (0.3811). Within population, heterozygosity was higher in Borduar (E2) (0.1093) and lowest in Titabar (E3) (0.0510). Highest gene flow (0.9035) was between E5 and E6 and the lowest (0.2172) was between E3 and E5. Regression analysis showed positive correlation between genetic distance and geographic distance among the populations. The high G(ST) value (0.657) among the populations combined with low gene flow contributes significantly to the genetic differentiation among the S. cynthia ricini populations. Based on genetic diversity, these populations can be considered as different ecotypes and in situ conservation of them is recommended.

Show MeSH

Related in: MedlinePlus

An example of PCR amplification profile generated from genomic DNA of S.c. ricini populations with UBC886, resolved on 1.5% agarose gel. M- marker. E1–E6 was the six populations as given in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2990324&req=5

i1536-2442-6-30-1-f02: An example of PCR amplification profile generated from genomic DNA of S.c. ricini populations with UBC886, resolved on 1.5% agarose gel. M- marker. E1–E6 was the six populations as given in Table 1.

Mentions: Twenty ISSR primers generated a total of 92 bands, of which 53 were polymorphic (Table 2; Fig.2). AMOVA revealed 87% of inter-population genetic variability and the PhiPT value was 0.872, which was significant at a probability of 0.010. Analysis for pair-wise genetic distance revealed that the genetic distance was minimum between E5 and E6 populations (0.0654) and maximum between E4 and E3 (0.3811) populations (Table 3). The intra- population variability in terms of DNA polymorphism was highest in E2 (31.52%) and least in E5 and E6 (14.13%) (Table.4). The dendrogram shown in Figure 3 that resulted from the genetic dissimilarity matrix using UPGMA (Sneath and Sokal 1973) revealed that E5 and E6 were genetically closer than the other populations, and E3 formed an isolate.


Genetic diversity and differentiation among populations of the Indian eri silkworm, Samia cynthia ricini, revealed by ISSR markers.

Vijayan K, Anuradha HJ, Nair CV, Pradeep AR, Awasthi AK, Saratchandra B, Rahman SA, Singh KC, Chakraborti R, Urs SR - J. Insect Sci. (2006)

An example of PCR amplification profile generated from genomic DNA of S.c. ricini populations with UBC886, resolved on 1.5% agarose gel. M- marker. E1–E6 was the six populations as given in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2990324&req=5

i1536-2442-6-30-1-f02: An example of PCR amplification profile generated from genomic DNA of S.c. ricini populations with UBC886, resolved on 1.5% agarose gel. M- marker. E1–E6 was the six populations as given in Table 1.
Mentions: Twenty ISSR primers generated a total of 92 bands, of which 53 were polymorphic (Table 2; Fig.2). AMOVA revealed 87% of inter-population genetic variability and the PhiPT value was 0.872, which was significant at a probability of 0.010. Analysis for pair-wise genetic distance revealed that the genetic distance was minimum between E5 and E6 populations (0.0654) and maximum between E4 and E3 (0.3811) populations (Table 3). The intra- population variability in terms of DNA polymorphism was highest in E2 (31.52%) and least in E5 and E6 (14.13%) (Table.4). The dendrogram shown in Figure 3 that resulted from the genetic dissimilarity matrix using UPGMA (Sneath and Sokal 1973) revealed that E5 and E6 were genetically closer than the other populations, and E3 formed an isolate.

Bottom Line: Samia cynthia ricini (Lepidoptera: Saturniidae), the Indian eri silkworm, contributes significantly to the production of commercial silk and is widely distributed in the Brahmaputra river valley in North-Eastern India.The high G(ST) value (0.657) among the populations combined with low gene flow contributes significantly to the genetic differentiation among the S. cynthia ricini populations.Based on genetic diversity, these populations can be considered as different ecotypes and in situ conservation of them is recommended.

View Article: PubMed Central - PubMed

Affiliation: Seribiotech Research Laboratory, Central Silk Board, CSB Campus, Kodathi, Carmelram PO, Bangalore, Karnataka, India. kvijayan01@yahoo.com

ABSTRACT
Samia cynthia ricini (Lepidoptera: Saturniidae), the Indian eri silkworm, contributes significantly to the production of commercial silk and is widely distributed in the Brahmaputra river valley in North-Eastern India. Due to over exploitation coupled with rapid deforestation, most of the natural populations of S. cynthia ricini are dwindling rapidly and its preservation has become an important goal. Assessment of the genetic structure of each population is a prerequisite for a sustainable conservation program. DNA fingerprinting to detect genetic variation has been used in different insect species not only between populations, but also between individuals within a population. Since, information on the genetic basis of phenotypic variability and genetic diversity within the S. cynthia ricini populations is scanty, inter simple sequence repeat (ISSR) system was used to assess genetic diversity and differentiation among six commercially exploited S. cynthia ricini populations. Twenty ISSR primers produced 87% of inter population variability among the six populations. Genetic distance was lowest between the populations Khanapara (E5) and Mendipathar (E6) (0.0654) and highest between Dhanubhanga (E4) and Titabar (E3) (0.3811). Within population, heterozygosity was higher in Borduar (E2) (0.1093) and lowest in Titabar (E3) (0.0510). Highest gene flow (0.9035) was between E5 and E6 and the lowest (0.2172) was between E3 and E5. Regression analysis showed positive correlation between genetic distance and geographic distance among the populations. The high G(ST) value (0.657) among the populations combined with low gene flow contributes significantly to the genetic differentiation among the S. cynthia ricini populations. Based on genetic diversity, these populations can be considered as different ecotypes and in situ conservation of them is recommended.

Show MeSH
Related in: MedlinePlus