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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.

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Map of North- Eastern India showing the places of collection of the eri silkworm, S.c. ricini populations. E1–E6 was the six populations as given in Table 1 (map not to scale).
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i1536-2442-6-30-1-f01: Map of North- Eastern India showing the places of collection of the eri silkworm, S.c. ricini populations. E1–E6 was the six populations as given in Table 1 (map not to scale).

Mentions: Six morphologically distinct populations of S. cynthia ricini, collected from different regions of North-eastern India (Table 1, Fig. 1), were used for the study: Nongpoh (E1), Borduar (E2), Titabar (E3), Dhanubhanga (E4), Khanapara (E5) and Mendipathar (E6). From each population, 10 to 15 cocoons were collected and kept until emergence of the adult moth. Genomic DNA from 10 individual moths of each population was extracted separately following the phenol: chloroform extraction method (Suzuki et al. 1972). After RNAse incubation, DNA was re-extracted and the purified DNA was diluted in TE (Tris-EDTA; pH 8.0) buffer to obtain the concentration of DNA at 10ng/μl.


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)

Map of North- Eastern India showing the places of collection of the eri silkworm, S.c. ricini populations. E1–E6 was the six populations as given in Table 1 (map not to scale).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

i1536-2442-6-30-1-f01: Map of North- Eastern India showing the places of collection of the eri silkworm, S.c. ricini populations. E1–E6 was the six populations as given in Table 1 (map not to scale).
Mentions: Six morphologically distinct populations of S. cynthia ricini, collected from different regions of North-eastern India (Table 1, Fig. 1), were used for the study: Nongpoh (E1), Borduar (E2), Titabar (E3), Dhanubhanga (E4), Khanapara (E5) and Mendipathar (E6). From each population, 10 to 15 cocoons were collected and kept until emergence of the adult moth. Genomic DNA from 10 individual moths of each population was extracted separately following the phenol: chloroform extraction method (Suzuki et al. 1972). After RNAse incubation, DNA was re-extracted and the purified DNA was diluted in TE (Tris-EDTA; pH 8.0) buffer to obtain the concentration of DNA at 10ng/μl.

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