Smart parasites? It sounds ominous, but new research into malaria parasites is giving scientists a better understanding of disease transmission. It seems that the malaria parasite is able to increase its own transmission rate by ‘relapsing’ during the times that the host animal is bitten by the insects that are capable of spreading it.
Researchers worked with domestic canaries infected with Plasmodium relictum, which is the most common parasite involved in cases of bird malaria in Eastern songbirds. They found that when the canaries were bitten by uninfected mosquitoes, parasite numbers in their blood increased, which in turn resulted in higher infection rates of the mosquitoes.
Pretty efficient. So how can understanding parasite evolution help us? Ultimately, understanding the factors that lead to these ‘relapses’ could help researchers develop better ways to control the disease. While it’s not yet known whether this type of transmission is present in humans, there are many other human pathogens that can also relapse after dormant periods (such as HIV, Herpes Simplex, and Mycobacterium tuburculosis), so it’s possible that this research could help scientists understand potential triggers for relapse in these diseases, as well. Read more about it here:
In an incredible research study, scientists studied juvenile bichir (a type of fish) on land to understand the evolutionary changes that may have taken place about 400 million years ago. That’s right- teaching fish how to walk is teaching researchers about evolution! These African fish are unique because they have lungs AND gills, and juveniles will sometimes walk on their fins. Researchers believe that bichirs walk in a way that is similar to early tetrapod ancestors.
When scientists looked at the differences in walking ability between bichirs raised in an aquatic environment versus bichirs raised in a terrestrial environnment, they found that the terrestrial animals became much more efficient at walking. What’s more, their anatomy began to change to facilitate walking!
This research suggests that organisms’ anatomy is changed in response to environmental changes. This is called developmental plasticity. The theory is that developmental plasticity gave early ancestors of tetrapods the ability to walk onto land. Once in a terrestrial environment, the animals were forced to evolve more quickly to keep up with the environment.
This research is amazing, because scientists pretty much created a snapshot of evolution right in the laboratory! They also provided a pretty good basis for the argument that plasticity was important in the evolutionary steps that led to walking. Read more about it here: http://www.nature.com/news/how-fish-can-learn-to-walk-1.15778
Electric eels are fascinating animals, not only because they look pretty cool, but also because they can generate electricity and deliver shocks of up to 600 volts. But they’re not the only fish that can produce electric fields, and recently, research at the University of Wisconsin, Madison has yielded some surprising information about the evolution of this ability- and what it could mean for other species.
Researchers analyzed the genes of the electric eel as well as other electric fish from unrelated families. It appears that there are a limited number of ways to evolve electric organs, and in at least six different fish, their electric organs evolved in the same way.
So… why should we care? By understanding the way electric organs were created through evolution, scientists may be able to gain the information needed to one day create electric organs in humans or other other animals. The zebrafish, a commonly used research animal, may play a role in attempts at this type of modification. If humans were able to have electric organs, they could possibly serve to power pacemakers, neurostimulators, or other implanted medical devices. Read more about it here:
In yet another example of the similarities between mice and men, researchers have found that males of the mouse species aren’t very likely to turn down sex, even when they’re not feeling that great. On the other hand, feeling under the weather definitely affects a female mouse’s sex drive. When experiencing pain, female mice had much less sexual motivation than usual. But when males were experiencing pain, it didn’t have any effect on the frequency of sexual behaviors displayed.
Sounds pretty similar to a lot of human relationships. The husband of a friend of mine was in the emergency room, waiting for x-rays on his broken ankle, but still suggested that she draw the curtains so they could have a little fun. She thought he was crazy; he thought it was a valid option.
While it’s too early to draw conclusions about complex human behavior from one mouse study, the results do suggest that sexual repression in females may be more biological than emotional in some cases. Could this be evolution at work? Interesting. What are your thoughts?
Past research has suggested a mechanism for the formation of distinct stripes (did you know that stripes are magnetic?), but new research helps to explain the evolution of these beautiful patterns.
Researchers at UC Davis looked at the geographical ranges of zebras and some of their closest geographic relatives, and surprisingly, they found that camouflage, temperature, or environment variations weren’t nearly as significant as the presence of flies. It appears that in parts of the world where biting flies are more of a problem, the amount of body striping is increased.
The evolution of the zebra’s stripes may have just gotten more interesting! We know that horseflies avoid striped surfaces, and understanding how and why certain animal characteristics evolved can be really important. Not only can it help us in conservation efforts, but we can potentially use this information to develop new techniques that can help humans and companion animals! I see some zebra-striped fly sheets in my horse’s future…
If you’re a parent, you’ve probably had several experiences where you FREAK OUT at others’ lack of caution with your (or their!) kids. From allowing your 5-year-old to ride a bike without a helmet, showing a PG-13 movie at an 8-year-old’s sleepover, tossing your infant in the air WAY too high for comfort, or letting your 2-year-old experiment with throwing random items into a toilet to see what will happen, moms everywhere have laundry lists of “NO-NO’s” that are usually not followed by dads other caregivers.
But let me introduce you to a dad who will DEFINITELY not win a father of the year award. Meet the male dyeing poison frog- after his baby tadpoles hatch, he carries the newborns to pools of water with older, cannibalistic tadpoles, drops them in, hops away, and hopes for the best.
Moms everywhere just went “WHAAAT?” But hear him out- just like your significant other caregivers you might know, they have what they think is a REALLY GOOD REASON for this. Apparently, they have a pretty good probability of surviving (although definitely not high enough to make moms happy), and since those older, cannibalistic tadpoles are growing and healthy, the pool must be a good spot.
Learning about the evolution of this strange reasoning could help researchers understand this behavior- both in frogs and in humans. And maybe now you’ll think that letting your little one experiment with toilet science isn’t quite as big of a deal…
Plenty of traits are passed down from one generation to the next. Eye color, hair color, height, body type- but did you know that offspring can also inherit a parent’s trauma?
Studies in the past have shown that women who have experienced trauma tend to have lower levels of the stress hormone cortisol. Children of these women also had lower cortisol levels. And it might be expected that if a mother has experienced trauma and is stressed, her kids would be stressed due to her own behavior.
But a new study shows that nature AND nurture both play a role in this- that traumatic experiences can be transferred to the offspring through sex cells! Male mice were trained to fear a particular odor. During the process, this learning changed neuronal organization in the mouse’s nose. Then, IVF was performed with sperm from these males. Both the first and second generation offspring had similar neuronal organization in their noses, and they feared the same odor that their fathers did!
This shows that information stored in the brain is somehow transferred to sperm cells. Researchers don’t know how yet… but they’re working on it!
E. coli showing evolution? Yes! Researchers at Michigan State University have been growing Escherichia coli for 25 years, which is over 58,000 generations, in a project called the Long-Term Experimental Evolution project. And during this time, through studying 12 populations of E. coli, they have found that the bacteria continues to adapt to its environment, with no upper limit in sight- even in the 40,00-50,000 generation range, E. coli‘s “fitness” (a measure of how the organism has adapted to its environment) increased by 3-4% per generation!
Another interesting find: several genetic changes that took place over thousands of generations allowed one of the E. coli colonies to develop the ability to eat the chemical citrate in the presence of oxygen (an ability that E. coli hasn’t had since the Miocene epoch!). Careful record-keeping allowed the researchers to look back at previous generations and track the development of this ability.
Just a fun fact for you- it would take almost two and a half million years to look at 58,000 generations of humans. Bacteria and animals with short lifespans can give us incredible insights into genetic changes that we wouldn’t be able to see in humans.