Site icon Zeeshan A. Mirza


Molecular basis of phenotypic plasticity in the nematode Pristionchus triformis

Pristionchus triformis Mg form feeding on P. pacificus. The lower pannel shows the three different mouth-forms.

Phenotypic plasticity driven in response to the environment leads to novelty which drives evolution. The nematode genus Pristionchus is an ideal model for investigating the molecular mechanism that governs plasticity. I hope to employ forward and reverse genetic tools to elucidate the molecular machinery governing mouth-form plasticity in the nematode Pristionchus triformis, which exhibits three mouth-related forms, stenostomatus (St), eurystomatus (Eu) and megastomatus (Mg), as opposed to two canonical mouth forms St and Eu in the established model Pristionchus pacificus. The Mg form serves as an additional avenue to explore the origin of plasticity in these nematodes and how the same gene regulatory network gives rise to yet another form (hypothesised). The Mg form may be an ideal biological pest controller in nematode-infested agricultural fields as it is predatory and, thereby, a species worth attention from the point of evolutionary studies and pest management.

Regeneration of legs in spiders

Plexippus paykulli showing regenerated leg indicated by the red arrow (left panel). Top image on the right panel shows microCT scan on an undamaged spider leg (control) vs regenerated leg showing tissue arrangement(lower right panel).

Many organisms can replace tissue, organs, and even most of the body by regrowing or repatterning somatic tissue. The study of such organisms that exhibit this remarkable ability will shed light on newer avenues in the field of medical sciences, especially concerning the treatment of injuries and diseases. There are many animals across the animal kingdom, especially invertebrates and a few vertebrates, which exhibit the remarkable ability for regeneration. Planaria and Hydra are among the well-known examples of model organisms to study regeneration besides crustaceans, cockroaches and crickets among invertebrates. Some members of Arachnida have the potential to regenerate lost limbs and/or parts of their bodies. Spiders (Order Araneae) are predatory arthropods (with only a few exceptions) that belong to the class Arachnida. They are distributed nearly throughout the globe except for Antarctica with well over 49,600 species in 129 families. Spiders have been of interest largely because of their role as biological pest controllers in nature and the venom and silk (web) as high tensile strength. Spiders are carnivorous and capture prey by several means, which include building elaborate web structures, trapdoor nets to ambush their prey. Besides this, they have the remarkable ability to grow their lost limbs and or parts of the chelicerae, labium and sternum. This ability is documented in the literature by mostly arachnologists and/or hobbyists. In the present work, I propose to explore the regenerative potential of the jumping spider Plexippus paykulli and present evidence for its regenerative abilities and propose it as a model to study appendicular regeneration. The species, Plexippus paykulli is a member of the family Salticidae and is commonly found in houses and around human habitation. The species is easy to rear and an ideal model to study the development of spiders, regeneration, cognitive behaviour, the jumping ability and its implications in robotic and the role of the species as a biological pest controller in urban landscapes. 


Systematics of Indian squamates and arachnids

A summary collage highlighting taxa of interest explored through an integrated taxonomic approach

The varied topography of India has led to the formation of diverse climatic regimes that shape the landscape which influences its biota. With distinct zoogeographic realms, it hosts diverse biota and boasts a high degree of endemism, especially in the biodiversity hotspots. The Himalayas, Indo-Burma and the Western Ghats hotspot are known to host rich biodiversity that offers endless avenues for biodiversity research, from taxonomy, evolutionary biogeography to conservation. In addition to these biodiversity hotspots, deserts, grasslands, wetlands, add to the diverse habitats that support biota that is adapted to these habitats further adding to the diverse biota of the country. My collaborators and I work across the country to document the diversity of amphibians, arachnids and reptiles across the country with an integrated approach. The main focus of the project is to resolve the systematics of taxa of our interest to elucidate their evolutionary history in the context of conservation of the species and landscape.


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