EC Veterinary Science

Research Article Volume 8 Issue 2 - 2023

Population Genetic Studies of Silkworm (Bombyx mori L.) Reared in Bulgaria and Phylogenetic Relationships

Teodora Atanasova Staykova*

Department of Developmental Biology, Section of Genetics, University of Plovdiv "Paisii Hilendarski", Plovdiv, Bulgaria

*Corresponding Author: Teodora Atanasova Staykova, Department of Developmental Biology, Section of Genetics, University of Plovdiv "Paisii Hilendarski", Plovdiv, Bulgaria.
Received: January 05, 2023; Published: January 27, 2023

The mulberry silkworm (Bombyx mori L.) is a species of great economic importance. Currently, there is a great variety of breeds, which is related to their different origins, as well as the selective activities carried out in different breeding centers around the world. Various methods have been used to assess genetic diversity in this species. One of them is the method of polyacrylamide gel electrophoresis (PAGE), which is used in the present work.

This study aimed to evaluate the degree of genetic variability and phylogenetic relationships between thirteen breeds of mulberry silkworm (Bombyx mori L.) from genetic resources of Bulgaria through isozyme polymorphism. PAGE was used. Among nine studied isoenzyme loci, by eight loci (Bes A, Bes B, Bes D, Bes E, Pgm A, Mdh A, Bph and Alp A) was found intra-breed and inter-breed polymorphism. At the Hk locus, we found inter-breed polymorphism only. The number of alleles per polymorphic locus ranged from one to two. The degree of polymorphism ranged from 0% to 77.80%. Low levels of observed heterozygosity in comparison with the expected one have been calculated in all of breeds. The combined FIS value over all polymorphic loci was 0.3205, which reflects a substantial deficit of heterozygotes. The value of FST showed that 49.21% of the overall genetic diversity observed was among breeds. The dendrogram constructed manifested that the two breeds of Japanese origin (Daizo and Japanese 106) were genetically most distant from other breeds. The data for isoenzyme polymorphism and genetic structure of the tested breeds can be used for genetic improvement and to develop new hybrids for silk production.

Keywords: Bombyx mori; Isoenzyme Polymorphism; Phylogenetic Relationships

  1. Eguchi M., et al. “A novel variant of acid phosphatase isozyme from hemolymph of the silkworm, Bombyx mori”. The Japanese Journal of Genetics2 (1988): 149-157.
  2. Marcato S., et al. “Variabilita di sistemi gene-enzima, in razze di Bombyx mori (Lepidoptera, Bombycidae) utilizzate per la produzione di seta”. Estratto da Redia2 (1990): 595-608.
  3. He JL. “Studies on the inheritance of a deletion type of the blood esterase isoenzymes in the silkworm, Bombyx mori L”. Sericologia1 (1995): 17-24.
  4. Staykova TA. “Genetically-determined polymorphism of nonspecific esterases and phosphoglucomutase in eight introduced breeds of the silkworm, Bombyx mori, raised in Bulgaria”. Journal of Insect Science18 (2008): 1-8.
  5. Moorthy SM and Chandrakanth N. “Analysis of phenotypic diversity and protein polymorphism in some silkworm breeds of Bombyx mori L”. Munis Entomology and Zoology2 (2015): 478-485.
  6. Staykova TA., et al. “Genetic analysis of isoenzyme polymorphism in silkworm (Bombyx mori) (Lepidoptera: Bombycidae) strains and phylogenetic relationships”. Acta Zoologica Bulgarica 67.1 (2015):117-125.
  7. Kaidanov LZ. “Genetics of populations”. Moscow: High school, Russia (1996): 320.
  8. Bindroo BB and Moorthy SM. “Genetic divergence, implication of diversity, and conservation of silkworm, Bombyx mori”. Hindawi Publishing Corporation - International Journal of Biodiversity (2014): 1-15.
  9. Egorova ТA and Nasirillaev YN. “Polymorphic enzymes of silkworm and their using in breeding”. In State Committee of Science and Technics of Republic Uzbekistan. Tashkent, UZ: GFNTI Press (1993): 120.
  10. Staykova TA., et al. “Acid phosphatase as a marker for differentiation of silkworm (Bombyx mori) strains”. Biotechnology and Biotechnological Equipment2 (2010): 379-384.
  11. Staykova TA., et al. “Genetic variability in silkworm (Bombyx mori) strains with different origin”. Acta Zoologica Bulgarica 4 (2012): 87-92.
  12. Staykova TA., et al. “Isoenzyme polymorphism of silkworm Bombyx mori 1758 (Lepidoptera: Bombicidae) breeds from germplasm resources of Bulgaria”. Acta Zoologica Bulgarica, Supplement 15 (2020): 11-19.
  13. Staykova TA. “Electrophoretic analysis of haemolymph proteins during silkworm (Bombyx mori) ontogenesis”. International Journal of Industrial Entomology 14.1 (2007): 37-44.
  14. Staykova TA., et al. “Electrophoretic analysis of nonspecific esterases in silkworm (Bombyx mori) female genital organs and eggs”. International Journal of Industrial Entomology 9.1 (2004): 59-63.
  15. Staikova TA., et al. “Differentiation of silkworm (Bombyx mori) strains by isoenzyme markers”. Genetics and Breeding 38.1 (2009): 47-55.
  16. Stoykova TA., et al. “Electrophoretic analysis of nonspecific haemolymph esterases during silkworm (Bombyx mori) ontogenesis”. Sericologia 43.2 (2003): 153-162.
  17. Staykova TA. “Inter- and intra-population genetic variability of introduced silkworm (Bombyx mori) strains raised in Bulgaria”. Journal of Bioscience and Biotechnology 2.1 (2013): 73-77.
  18. Davis BJ. “Disc electrophoresis II. Method and application to human serum proteins”. Annals of the New York Academy of Sciences2 (1964): 404-427.
  19. Staykova TA., et al. “Genetic characterization of silkworm (Bombyx mori) strains (Lepidoptera: Bombicidae) with different geographical origin on the basis of isozyme markers”. Acta Scientiarum – Biological Sciences 42 (2020): e4797.
  20. Nei M. “Genetic distance between populations”. The American Naturalist949 (1972): 283-292.
  21. Wriht S. “The interpretation of population structure by F-Statistics with special regard to systems of mating”. Evolution3 (1965): 395-420.
  22. Swofford DL and Selander RB. “BIOSYS-1: A computer program for the analysis of allelic variation in genetics”. Rel. 1.0. Urbana, IL: Department of Genetics and Development University of Illinois at Urbana-Champaign (1981).
  23. Sneath PHA and Sokal RR. “Numerical Taxonomy: The principles and practice of numerical classification”. San Francisco, CA: W.H. Freeman and Co (1973): 573.
  24. Felsenstein J. “PHYLIP (Phylogeny Inference Package). Version 3.5c”. Seattle, WA: University of Washington (1993).
  25. Egorova TA., et al. “Polymorphic system of silkworm haemolymph esterases as a criterion to make programs for parental specimens crossing”. Biochemistry of Insects (1985): 54-62.
  26. Maqbool A., et al. “Haemolymph esterase and peroxidase spectra in bivoltine silkworm (Bombyx mori) genotypes and their utility”. Journal of Cell and Tissue Research 15.3 (2015): 5193-5199.
  27. Shabalina A. “Esterase genetic polymorphism in haemo-lymph of larvae Bombyx mori L”. Comptes Rendus De l'Academie Bulgare Des Sciences9 (1990): 105-108.
  28. Eguchi M., et al. “Types and inheritance of blood esterase in the silkworm, Bombyx mori L”. Japan Journal of Genetics1 (1965): 15-19.
  29. Mirhoseini SZ., et al. “Genetic characterization of Iranian native Bombyx mori strains using amplified fragment length polymorphism markers”. Journal of Economic Entomology3 (2007): 939-945.
  30. Liu YQ., et al. “Comparative genetic diversity and genetic structure of three Chinese silkworm species Bombyx mori (Lepidoptera: Bombycidae), Antheraea pernyi Guérin-Meneville and Samia cynthia ricini Donovan (Lepidoptera: Saturniidae)”. Neotropical Entomology 39.6 (2010): 967-976.
  31. Lande R. “Risk of population extinction from fixation of new deleterious mutations”. Evolution5 (1994): 1460-1469.
  32. Whitlock MC. “Selection, load and inbreeding depression in a large metapopulation”. Genetics3 (2002): 1191-1202.

Teodora Atanasova Staykova. Population Genetic Studies of Silkworm (Bombyx mori L.) Reared in Bulgaria and Phylogenetic Relationships. EC Veterinary Science  8.2 (2023): 02-11.