A Belgian cemetery has been overrun with unnatural mutant crayfish, The New Zealand Herald reported. The all-female horde of crustaceans don’t require males to reproduce and were initially created in a breeding program. Understanding cloning begins with a look at cells.
According to The New Zealand Herald, a species of crayfish is causing a major problem in Belgium. “Escaped self-cloning mutant crayfish created in experimental breeding programs have invaded a Belgian cemetery,” the article said. “Hundreds of the duplicating crustaceans, which can dig down to up to a meter and are always female, pose a deadly threat to local biodiversity after colonizing a historic Antwerp graveyard.
“They are similar to the slough crayfish found in Florida but are parthenogenetic, which means they reproduce with themselves and all their children are genetically identical females.”
What’s Up, Doc?
One of the first major cloning experiments was performed by Frederick Steward at Cornell University in 1958.
“[Steward] took specialized cells from the root of a carrot plant and put them into a growth medium that would signal these cells to become embryo cells,” said Dr. David Sadava, Adjunct Professor of Cancer Cell Biology at the City of Hope Medical Center in Duarte, California. “The cells indeed formed a carrot embryo, and then that grew up into a functional carrot that had roots, stems, leaves, and flowers—all the organs of a plant.
“And if he did five cells from the carrot, he got five identical carrots. They were clones.”
The difference between a clone and a normal offspring is that a clone is genetically identical to the cell from which it came. In this instance, that means the root cell from the original carrot. Dr. Sadava said that cloning in plants can be done for many different kinds of plant cells and organs. Scientists have identified different chemical signals that can turn one cell type into another, making them versatile and easy to work with in cloning.
When scientists clone plants, the clones grow into fully formed plants complete with reproductive organs. What about animals?
“Some simple animals can regenerate organs from other cells,” Dr. Sadava said. “For example, worms, the little hydra that live in fresh water, and starfish can regenerate organs. In these animals that can, their specialized cells are easily manipulated by injury or some other purpose, and they’re plastic in their genetic program.”
This means that they have the genes and the genes can be turned on at will. However, most complex animals can’t do so. Dr. Sadava said that understanding of animal cloning comes from the cell’s nucleus. The nucleus is the location of the cell’s genetic material.
“The idea was, let’s surround not the whole cell with some chemical signals, but let’s surround the cell nucleus with the chemical environment that says ‘You’re in a fertilized egg now; you’re not in a skin cell,'” he said. “This can be done by a little bit of surgery. We can replace the nucleus of the egg with the nucleus of a specialized cell, and thereby we’ll give that nucleus of the specialized cell the ‘eggy’ environment.”
Usually this is done with pipettes, which are like incredibly small straws. The pipettes can suck out the nucleus of an egg cell and insert the nucleus of another cell. From there, the cloned cell begins to grow.
Dr. David Sadava contributed to this article. Dr. Sadava is Adjunct Professor of Cancer Cell Biology at the City of Hope Medical Center in Duarte, CA, and the Pritzker Family Foundation Professor of Biology, Emeritus, at The Claremont Colleges. Professor Sadava graduated from Carleton University as the science medalist with a BS with first-class honors in biology and chemistry. A Woodrow Wilson Fellow, he earned a PhD in Biology from the University of California, San Diego.