Call them Franken flatworms. Scientists have created worms with the heads and brains of other species just by manipulating cell communication. 
 
 The research is an example of how development is controlled by more than genetics alone. The researchers did not alter the flatworms' DNA in any way, but instead manipulated proteins that control conversations between cells. 
 
 "It is commonly thought that the sequence and structure of chromatin — the material that makes up chromosomes — determine the shape of an organism, but these results show that the function of physiological networks can override the species-specific default anatomy," study researcher Michael Levin, a biologist at Tufts University, said in a statement. [See Photos of the Franken Flatworms with Different Heads, Brains] 
 
 The changes are temporary for the worms, whose heads begin to revert back to their original shapes in weeks. But researchers hope the findings will lead to treatments for birth defects and even regenerative medicine, which aims to replace or rebuild damaged tissues and organs. 
 
 The researchers studied a small freshwater flatworm, Girardia dorotocephala, which is known for being able to regenerate lost tissues. These flatworms retain a large number of cells called neoblasts, which are totipotent stem cells, meaning they can become any cell type in the body. In humans, cells are totipotent only in the first days of embryonic development. 
 
 First, the scientists cut off the heads of their lab specimens. Next, to alter the flatworm's regenerating head, Levin and his colleagues interrupted protein channels called gap junctions. Cells send electrical impulses through these junctions in order to communicate. The researchers found that they could easily nudge the worm to develop head and brain shapes similar to those of other closely related flatworm species. 
 
 Normally, G. dorotocephala sports a pointy head with two elongated, earlike projections (called auricles) next to the eyes. After treatment, some of the worms developed their normal heads, while others grew rounded heads like those of S. mediterranea; heads with thick necks and pointy, catlike "ears" like those of P. felina; or triangular heads like those of D. japonica. 
 
 The brains seemed to follow suit with the altered head shape, so that flatworms that regenerated a head shaped like that of D. japonica, for instance, also showed brain morphologies that were shorter and wider than those of G. dorotocephala and more characteristic of D. japonica. 
 
 The farther two species were from each other on the evolutionary family tree, the harder it was to induce this mix-and-match effect, the researchers reported online Nov. 24 in the International Journal of Molecular Sciences. 
 
 "These findings raise significant questions about how genes and bioelectric networks interact to build complex body structures," Levin said. If genes provide a blueprint for an organism's body, cells are like the construction workers required to turn the plan into a structure — and gap junctions are the walkie-talkies these workers use to communicate. Disrupt the communications, and you can disrupt the building process. 
 
 G. dorotocephala remained altered for only a limited amount of time before its neoblasts took over and reasserted the old head and brain shapes. However, Levin's lab previously engineered another species of flatworm to grow two heads and stay that way. 
 
 Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science. ||||| Biologists at Tufts University have succeeded in inducing one species of flatworm to grow heads and brains characteristic of another species of flatworm without altering genomic sequence. The work reveals physiological circuits as a new kind of epigenetics -- information existing outside of genomic sequence -- that determines large-scale anatomy. 
 
 The finding that head shape is not hard-wired by the genome but can be overridden by manipulating electrical synapses in the body suggests that differences in species could be determined in part by the activity of bioelectrical networks. The discovery could help improve understanding of birth defects and regeneration by revealing a new pathway for controlling complex pattern formation. It has long been known that neural networks exploit bioelectric synapses to store and re-write information in the brain. 
 
 The findings are detailed in the cover story of the November 2015 edition of the International Journal of Molecular Sciences, appearing online Nov. 24. 
 
 "It is commonly thought that the sequence and structure of chromatin -- material that makes up chromosomes -- determine the shape of an organism, but these results show that the function of physiological networks can override the species-specific default anatomy," says the paper's senior and corresponding author Michael Levin, Ph.D., who holds the Vannevar Bush Chair in biology and directs the Center for Regenerative and Developmental Biology in the School of Arts and Sciences at Tufts. "By modulating the connectivity of cells via electrical synapses, we were able to derive head morphology and brain patterning belonging to a completely different species from an animal with a normal genome." 
 
 Knowing how shape is determined and how to influence it is important because biologists could use that knowledge, for example, to fix birth defects or cause new biological structures to grow after an injury, adds Levin. "These findings raise significant questions about how genes and bioelectric networks interact to build complex body structures," he says. 
 
 Working with Girardia dorotocephala -- free-living planarian flatworms, which have remarkable regenerative capacity -- researchers were able to induce the development of different species-specific head shapes by interrupting gap junctions, which are protein channels that enable cells to communicate with each other by passing electrical signals back and forth. The changes were more than skin deep; they included not only the overall shape of the head but also the shape of the brain and the distribution of the worm's adult stem cells. 
 
 The ease with which a particular shape could be coaxed from a G. dorotocephala worm was proportional to the proximity of the target worm on the evolutionary timeline. The closer the two species were related, the easier it was to effect the change. This observation strengthens the connection to evolutionary history, suggesting that modulation of physiological circuits may be one more tool exploited by evolution to alter animal body plans. 
 
 However, unlike the Levin lab's previous work, in which a different species of planaria could be permanently altered to a two-headed morphology, this shape change was only temporary. Weeks after the planaria completed regeneration to the other species' head shapes, the worms once again began remodeling and re-acquired their original head morphology. Additional research is needed to determine how this occurs. The authors also presented a computational model that explains how changes in cell-to-cell communication can give rise to the diverse shape types. 
 
 First author on the paper was Tufts undergraduate Maya Emmons-Bell, a senior majoring in biology. "We've demonstrated that the electrical connections between cells provide important information for species-specific patterning of the head during regeneration in planarian flatworms," she says. "This kind of information will be crucial for advances in regenerative medicine, as well as a better understanding of evolutionary biology. As an undergraduate, it's been an extraordinary experience to conduct and author important research with leading biologists." 
 
 The interdisciplinary research involved U.S.- and Canada-based biologists and European mathematicians. ||||| Flatworms are remarkable creatures, some of which have almost unbelievable abilities of tissue regeneration and growth. One particular species, Girardia dorotocephala, has been shown to be able to take this ability one bizarre step further: Researchers at Tufts University have successfully induced it to grow heads and certain brain structures of several other flatworm species on a temporary basis, all without altering its genetic sequence. Their findings are reported in the International Journal of Molecular Sciences. 
 
 The shape of an animal's body is largely determined by its genome. However, bioelectric networks of nerves and their connections (synapses) have their own way of forming constructs, and the careful manipulation of these can cause unique features to form in certain organisms, overriding the genetic material’s instructions. 
 
 With this in mind, the team of researchers decided to modify the synaptic connections in the head of their chosen flatworm to see if they could force it to produce new shapes. After decapitating them, the electrical connectivity between cells in its upper body were altered using a form of alcohol (octanol). 
 
 Incredibly, this caused the flatworms to grow not just new tissue, but entirely new heads – heads belonging to completely different species of flatworm: S. mediterranea, D. japonica, and P. felina. Not only were the head shapes replicated, but segments and characteristics of their brains were also seemingly copied, including the distribution of adult stem cells. The closer the two species were related, the easier it was for the researchers to induce the changes. 
 
 These changes, oddly, weren’t permanent: Within a few weeks, the genetic coding overcame the bioelectrically-induced head change, and their heads gradually returned to their original form. At present, the researchers aren’t entirely sure how this remodeling occurs. 
 
 Regardless, the fact that this all occurred without changing the DNA of the original flatworm is the study’s most significant discovery. This means that changes in a flatworm’s ability to “build” itself can sometimes originate from outside the instructions coded in its genetic material. This type of externally-induced alteration is known as epigenetics – literally meaning “extra growth.” 
 
 Transferring a selection of genes from two parents to their offspring isn’t the only way the building instructions for an organism are inherited. Along with an additional process called horizontal gene transfer employed by certain microscopic organisms, changes in the way genes are expressed can also be inherited. Several environmental or otherwise external factors can change the way cells read genes, meaning that the physical attributes of the offspring may be different – all without changing the DNA sequence. 
 
 Although it has yet to be shown whether or not these unusual flatworm changes can be transferred to their offspring, they do fit within the definition of epigenetics – although as some point out, without the inheritance being demonstrated, applying this definition can be somewhat controversial. 
 
 Nevertheless, the study has implications outside of just flatworm biology. Maya Emmons-Bell, a Tufts University biology undergraduate and first author on the paper, said in a statement: “This kind of information will be crucial for advances in regenerative medicine, as well as a better understanding of evolutionary biology.” 
 
 Image in text: G. dorotocephala (top left) was able to grow the heads of other species (top row) with no changes to its genome. Center for Regenerative and Developmental Biology, School of Arts and Sciences, Tufts University ||||| In French Revolution-style, researchers decapitated flatworms—then did something that would give even Madam Defarge the creeps. 
 
 The scientists let the worms’ heads grow back and found that their memories returned along with the new noggins, according to a new study in the Journal of Experimental Biology. 
 
 Michael Levin and Tal Shomrat, biologists at Tufts University, have been studying how animals store and process information, whether it’s memories in the brain or the blueprint for developing organs in the body. 
 
 The team turned to flatworms because, despite their relative simplicity, they have many of the same organs and body organization as people: a brain and nervous system, bilateral symmetry, and even some of the same behaviors. 
 
 Flatworms “also have many of the same neurotransmitters as we do, and have been shown in older studies to remember complex tasks,” Levin said. (Read more about memory in National Geographic magazine.) 
 
 Yet unlike people, these worms have a remarkable ability to regenerate organs and body parts, including their brains—making them perfect research subjects. 
 
 In the Spotlight 
 
 Planarian flatworms are a hugely diverse array of small non-parasitic worms found in both freshwater and saltwater environments. 
 
 They have primitive eyes that can detect light, which they generally avoid—being in light makes them more obvious to predators. 
 
 To train the worms that lighted areas were safe and contained food, the researchers used a computerized device to continually track the worms’ behavior, providing rewards when a worm ventured into the bright spots and punishments when it remained in the dark. 
 
 “We used this device to get worms used to a dish with a peculiar laser-etched surface. When they remember this surface, they will rapidly approach a piece of liver to eat it, as opposed to spending much time circling around the dish to get the lay of the land,” Levin said. 
 
 Off With Their Heads 
 
 After the team verified that the worms had memorized where to find food, they chopped off the worms’ heads and let them regrow, which took two weeks. 
 
 Then the team showed the worms with the regrown heads where to find food, essentially a refresher course of their light training before decapitation. 
 
 Subsequent experiments showed that the worms remembered where the light spot was, that it was safe, and that food could be found there. The worms’ memories were just as accurate as those worms who had never lost their heads. (Test your memory with a National Geographic game.) 
 
 Memory Beyond the Brain 
 
 The obvious question remains: How can a worm remember things after losing its head? 
 
 “We have no idea,” Levin admitted. “What we do know is that memory can be stored outside the brain—presumably in other body cells—so that [memories] can get imprinted onto the new brain as it regenerates.” 
 
 Researchers have long confined their investigations of memory and learning to the brain, Levin said, but these results may encourage them to look elsewhere. (Read about a tadpole that can see through an eye implanted on its tail.) 
 
 “We’ve established a new model system in which our future work will be able to figure out how memories get encoded and decoded to and from living tissues.” 
 
 And given that we can’t regrow their heads, it’s unlikely that decapitation will ever become a serious memory aid for frantic students before exams.
– Worms can grow the head and brain of another species? Then maybe we can do better at regenerating our own organs and tissues. That's the thrust of a new study by researchers who got flatworms to grow the heads of other flatworm species without any alteration to the worms' DNA, LiveScience reports. The researchers just altered the way proteins communicated between the flatworms' cells. "It is commonly thought that the sequence and structure of chromatin—the material that makes up chromosomes—determine the shape of an organism," says study researcher Michael Levin in a press release. "But these results show that the function of physiological networks can override the species-specific default anatomy." The researchers began by decapitating freshwater flatworms called Girardia dorotocephala, which are are able to regrow severed tissues; they have stem cells that can turn into any other kind of cell (we have similar cells, but only as early embyros). Researchers then used a kind of alcohol to alter electrical impulses that cells send through protein channels in the worms, IFL Science reports. Amazingly, some of the worms grew heads that were rounded, triangular, or had pointy ears—and all from other species. The worms eventually grew back their own heads, with their DNA fully intact. "This kind of information will be crucial for advances in regenerative medicine, as well as a better understanding of evolutionary biology," says Maya Emmons-Bell, first author of the study.