Question

The nematode, Caenorhabditis elegans genome encodes hundred of G-Protein Coupled Receptors (GPCRs) involved in responding to environmental stimuli. The nematode, Meloidogyne hapla genome encodes only a small handful of the same genes. What is a biological explanation for this drastic difference? Use information on the life cycles of these nematodes to inform your answer.

Short response

Answer 1

Meloidogyne hapla is a root parasite causing lot of damage to crops . It is a nematode. So the nematode is restricted to a particular environment. Where as Cenorhabditis elegans is free living in the soil,stems of plants, fruits, compost and present all over the world. C.elegans is exposed to varied environmental conditions and different chemicals present around. It should be able to identify and respond. For that purpose, it has many genes encoding GPCRs. These receptors respond to chemicals present in the surroundings and also responsible for olfacation and taste. Because there are variety of chemicals present in different surroundings, C.elegans has many genes encoding GPCRs. Where as the Meloidogyne hapla is restricted to a host plant and exposed to a only particular type of chemicals. Eggs released in to soil which develop in to juveniles. These once again invade the roots.