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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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Dendrogram showing grouping of 60 individuals from six populations of S.c. ricini based on the genetic distance derived from ISSR markers. Bootstrap values were given at the fork of each group. E1–E6 was the six populations as given in Table 1. E1.1 – One individual from the population E1.
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i1536-2442-6-30-1-f04: Dendrogram showing grouping of 60 individuals from six populations of S.c. ricini based on the genetic distance derived from ISSR markers. Bootstrap values were given at the fork of each group. E1–E6 was the six populations as given in Table 1. E1.1 – One individual from the population E1.

Mentions: When all 60 individuals were taken for analysis without assigning any population status, the individuals grouped according to their population affinity (Fig. 4). None of the individuals changed its population cluster. The bootstrap values for each population were highly significant and varied from 65 to 100. The grouping of individuals within each population showed variation. Though the individuals of different populations grouped into sub groups, in most cases, the bootstrap values were insignificant. But significantly high bootstrap values (71–99%) were observed in the subgrouping of the E2 population.


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)

Dendrogram showing grouping of 60 individuals from six populations of S.c. ricini based on the genetic distance derived from ISSR markers. Bootstrap values were given at the fork of each group. E1–E6 was the six populations as given in Table 1. E1.1 – One individual from the population E1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

i1536-2442-6-30-1-f04: Dendrogram showing grouping of 60 individuals from six populations of S.c. ricini based on the genetic distance derived from ISSR markers. Bootstrap values were given at the fork of each group. E1–E6 was the six populations as given in Table 1. E1.1 – One individual from the population E1.
Mentions: When all 60 individuals were taken for analysis without assigning any population status, the individuals grouped according to their population affinity (Fig. 4). None of the individuals changed its population cluster. The bootstrap values for each population were highly significant and varied from 65 to 100. The grouping of individuals within each population showed variation. Though the individuals of different populations grouped into sub groups, in most cases, the bootstrap values were insignificant. But significantly high bootstrap values (71–99%) were observed in the subgrouping of the E2 population.

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