Research
Identification and analysis of genes involved in sex determination pathway of silkmoths
Unlike Drosophila, mouse and humans, the chromosomal make-up of silkmoth is ZZ in males and ZW in females. The current hypothesis is that the presence or absence of a strong W-linked epistatic factor determines the sex of the organism. This is based on the fact that even in polyploids where there is a single W and several Z chromosomes, the resulting sex would be female. With the sex determination mechanism being established in Drosophila, Caenorhabditis elegans and mammals to the comparative analysis of the sex determination mechanism in silkmoth is feasible.
In the silkworm, males are known to produce more silk compared to the females, where a great proportion of the resources is channeled towards the production of ova. It would be advantageous if the sex ratio could be manipulated so as to produce only males. Also, silkworm belongs to the order Lepidoptera which includes several devastating pests. To name a few, cotton bollworm, tobacco hornworm etc., cause annually several billion dollars worth of crop loss, world over. Besides, a huge quantity of pesticides is required for the control of these pests. Knowledge about the sex determination mechanism in the silkworm would help devising methods to control these pests, again by the manipulation of the sex ratio.
Projects being pursued
- Genetics of sex determination in B. mori
- Evolution and conservation of sex determination mechanisms in silkmoths
Working group
Present Phd students
- Sawanth Suresh Kumar
- Gajula Gopinath
- Vandana
- Parveen Kumar
Past Phd students
- V Satish
- J N Shukla
Publications
- Arunkumar, KP and Nagaraju, J (2010) Drosophila intersex orthologue in the silkworm, Bombyx mori and related species. Genetica. 139:141-147
- Nagaraju J and Saccone G(2010) How is sex determined in insects?. J. Genet.
- Shukla JN and Nagaraju J (2010) Doublesex: a conserved downstream gene controlled by diverse upstream regulators. J. Genet. 89:341-356
- Nagaraju J and Saccone G (2010) How is sex determined in insects? An epilogue. J. Genetics
- Shukla JN, Jadhav S and Nagaraju J (2010) Novel female-specific splice form of dsx in the silkworm, Bombyx mori. Genetica (In press)
- Shukla JN and Nagaraju J (2010) Two female-specific DSX proteins are encoded by the sex-specific transcripts of dsx, and are required for female sexual differentiation in two wild silkmoth species, Antheraea assama and Antheraea mylitta (Lepidoptera, Saturniidae). Insect Biochemistry and Molecular Biology
- Marec F, Neven LG, Robinson AS, Vreysen M, Goldsmith MR, Nagaraju J, Franz G (2005) Development of genetic sexing strains in Lepidoptera: from traditional to transgenic approaches. Journal of Economic Entomology 98: 248-259.
- Priyadarshini P, Murthy BS, Nagaraju J, Singh L (2003) A GATA-binding protein expressed predominantly in the pupal ovary of the silkworm, Bombyx mori. Insect Biochemistry and Molecular Biology 33: 185-195.