Why are sticklebacks good for studying evolution?
Fish have used pre-existing genetic variation to colonize fresh water many times. Scientists have pinpointed mutations that may help a tiny armoured fish to evolve quickly between saltwater and freshwater forms.
Why are sticklebacks a model organism?
primary advantage of using threespine stickleback as a model organism is the ability to study how natural genetic variation, which is of a magnitude similar to that found in the human population (Fig. 2), influences a range of phenotypes, including bone development (66), pigmentation (67, 68), and behavior (69).
Why did stickleback lose its spines?
They lost them either because there was less calcium in freshwater to build bony tissue or because predatory insects like dragonfly nymphs — which would normally try to feed by grabbing the sticklebacks’ fins in their mouths — would have much less to grab.
In what type of water do the three-spined stickleback fish spawn in?
Fish in this species are anadramous, living in the ocean but entering brackish water or ascending freshwater streams to spawn. The male threespine stickleback not only builds the nest, he also guards it, takes care of the eggs, and protects the newly hatched larvae.
Does stickleback fish evolve?
Pockets of sticklebacks were isolated by geologic changes at the end of the Ice Age 10,000 years ago, with each newly separated population evolving in response to local ecological conditions.
Why are stickleback fish important?
Threespined sticklebacks (Gasterosteus aculeatus) are small fish that have proven to be a powerful model system for identifying the genetic mechanisms that underlie adaptive morphological evolution.
What is the difference between marine sea run and freshwater stickleback fish populations?
Marine stickleback populations live and breed strictly in the ocean. Sea-run stickleback fish are anadromous, meaning that they are born in fresh water, spend most of their lives in the ocean, and return to fresh water to breed. Freshwater stickleback fish live entirely in fresh water.
Do marine sticklebacks have pelvic spines?
Most marine stickleback fish have a pelvis with a protective spine, but stickleback fish from certain freshwater populations have a missing or reduced pelvis. As shown in the animation, Pitx1 is activated in the pelvic region during development in marine fish.
What is mutated in Pitx1 in freshwater sticklebacks?
Mike Shapiro, PhD, a postdoctoral scholar and co-first author, found that a gene located at that region is the stickleback version of a gene in mice called Pitx1 that, when mutated, causes mice to have greatly reduced hind limbs. These mice often have asymmetric limb and pelvic reductions, much like the sticklebacks.
Can you keep sticklebacks in a tank?
They tolerate a moderate range of conditions, but are susceptible to tanks that are too warm. Like many native fish, they will happily live in water down to 4°C/39°F, but above 20°C/68°F they suffer, their metabolisms increasing considerably. In most unheated tanks of 18°C/ 64°F or under, they will do just fine.