Daphnia pulex belongs to water flea species. It was the first crustacean to have its genome sequenced. It possesses approximately 31,000 genes (humans have about 23,000 genes). Daphnia pulex water fleas are tiny and translucent aquatic crustaceans. They are found in freshwater lakes, ponds, streams and rivers. Daphnia pulex currently holds the record of highest number of genes among all animals (like mice, yeast, bacteria, fruit flies and round worms) that have been gene sequenced so for.
There are many advantages of using Daphnia pulex water fleas in genetic research. They are ubiquitous and are found in abundance throughout the Americas, Europe and Australia. They form an important part of aquatic ecosystem. Daphnia pulex water flea is a keystone species in both ponds and lakes.
Daphnia pulex water fleas feed on algae, protozoa and bacteria. Both large and small fish feed on Daphnia pulex water fleas. Due to their important position in food chains, they are used to study the response of ecosystems to environmental change. These creatures are amenable to both field and laboratory study.
The reproductive cycle of Daphnia pulex is ideal for genetic study. Generation time ranges from ten to fifteen days. This makes it possible for research scientists to observe genome regulatory changes throughout its ontogeny (development from embryo to adult).
Daphnia pulex water fleas have a unique ability to alter their bodies in response to the surroundings. They have the ability to survive in polluted water. These creatures have been used for decades as a standard organism for toxicity testing. Their toxicological reactions to substances causing pollution are well characterized.
Daphnia pulex water fleas can increase or decrease their size in order to escape from their predators. According to experts, daphnia pulex water fleas have the ability to develop neck-teeth, spines and helmets to defend themselves. This adaptability is attributed to their high number of genes.
Research scientists are of the opinion that many of these genes are duplicate copies, each with a slightly different characteristic. These genes are completely new to science. These wonderful creatures have the ability to select appropriate genes to issue new instructions for building different proteins. That is how they alter their bodies.
"Genome research on the responses of animals to stress has important implications for assessing environmental risks to humans. Daphnia is an exquisite aquatic sensor, a potential high-tech and modern version of the mineshaft canary", says Dr James Klaunig of Indiana University.
Daphnia pulex water fleas are amazing creatures. They never cease to fascinate biologists.