Though skin cancer is deadly to male fish, it also has one perk: The black melanoma splotches arise from attractive natural markings that lure female mates.
A new study published in the Proceedings of the National Academy of Sciences this week shows that the melanoma gene can be conserved in swordtail fish because of its beneficial role in sexual selection.
Ohio University scientists André Fernandez and Molly Morris studied three populations of female swordtails, tiny freshwater fish native to North and Central America, and found that two of them preferred males whose tails were painted to resemble the skin cancer spots. The researchers also examined specimens of swordtail fish with real melanomas, which confirmed that the cancer gene is switched on only in the tissue with the dark pigment. The study marks the first time scientists have found a cancer gene linked to a pigment pattern that functions to increase mating success in animals.
In the current study, the researchers placed a female swordtail in the middle of a tank with two partitions. They positioned a male with the faux pattern from which melanomas form on one side, and a male without the pattern on the other. After releasing the female from an opaque tube into the tank's center chamber, the scientists observed how much time she spent looking at each male during an eight-minute period. The project builds on previous studies in the Morris lab, which used the same tests to show that female swordtails are strongly attracted to males with dark vertical bars.
To avoid any bias the female might have for a particular side of the tank, Fernandez then switched the males. Two days later, he conducted the trials again, this time changing which male received the painted skin cancer spot. The female consistently chose the male with the dark pigmented marking in two of the three populations, he said.
But the research suggests that the swordtail fish population also keeps the prevalence of the cancer gene in check. A third population of females in the study rejected the males painted with the pattern that can form melanomas. The scientists suspect that's because the third group had a higher ratio of both males and females with the gene for skin cancer, which increases the likelihood of too many offspring inheriting the gene and dying off.
Swordtail fish usually live for 1.5 to 2 years in the wild and sexually mature at 4.5 months. The ones with the skin cancer gene can develop melanomas at about 7 months and die a few months later.
"Melanoma formation cuts the reproductive life cycle in half," Fernandez said. "It has a huge cost for males."
But during the few months when the male is sexually mature and healthy, he also can produce a lot of offspring, he noted.
The swordtail melanoma has been studied since the 1920s, and scientists previously believed that fish developed the cancer only in captivity. But in the recent study, 10 percent of the swordtails collected from the third population in Mexico also exhibited the disease, said Fernandez, who joins the University of Texas M.D. Anderson Cancer Center this fall as a postdoctoral fellow. He hopes to conduct further studies on the habitat, such as whether stronger exposure to the sun's UV rays might be driving more instances of skin cancer in the wild.
Andrea Gibson | EurekAlert!
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences