Convergent Evolution of Silks in Arthropods

This article details a study regarding the convergent evolution of silk production in a few different arthropods. In particular, the study selected a type of butterfly, three types of caddisfly, and a type of spider. They each had different uses for their types of silk. They found that the variation in silk gene alleles are relatively consistent when compared between organisms which have long since been independently evolving. They suggested that this means there are common mechanisms for the formation of those genes within organisms. The researchers stress that they would like to repeat this study with other organisms which share similar traits but evolved independently. 

    The topic of convergent evolution is one that has always intrigued me. I am particularly interested in the pathways that evolution takes to develop similar traits despite independent evolution of organisms… As well as the fact that the above study could be replicated and utilized to study other traits relative to convergent evolution. Not only am I interested in the replication of this study, but the evolution of silk producing glands and maintenance of them in arthropods is such a cool concept. Overall, I look forward to seeing what other types of evolutionary genetic comparisons these researchers go on to make.

Extraction of Ancient Insect DNA from Copal!

 

This article discusses the ability to extract ancient DNA from insects trapped in copal. It tests the hypothesis of whether or not aDNA (ancient DNA) could possibly be preserved over such an extensive period of time. They were able to extract endogenous DNA molecules from one of the samples they analyzed, and able to make taxonomic identifications regarding the organism, though it was incredibly degraded. They did so via radiocarbon analysis. They discuss struggles regarding human DNA contamination, and how tedious the separation of modern human DNA from the aDNA was. Additionally, they discuss reasons behind why they advise against this type of analysis- it is highly destructive to the samples.

I am highly interested in the extraction, sequencing, and use of ancient DNA in modern studies. Therefore, it is not surprising that I find this article incredibly fascinating. Scientifically, I find this an incredible feat, which is primarily attributed to the fact that DNA degrades so quickly. It is absolutely insane to think that we may be able to extract ancient biomolecules, and harness the ability to not only make assumptions about ancient organisms, but also use the information gathered to make strides in modern genetic research. 

Extraction of Insect DNA From The Air!

    This article details how we have a high estimate of the total number of species on this planet. It discusses how many species we have discovered in comparison to our early highest estimates, and provides a potential solution. Our current method of identifying new species around the world is incredibly slow, only moving forward by people actively going in the field, collecting, and describing species. Additionally, rates of species discovery grow increasingly slower as the species decrease in size. However, this new form of technology would allow the capture of DNA from within the air. It costs less, and is faster than traditional sampling methods, and, additionally, can ID many species simultaneously. Airborne samples are collected using something called a liquid cyclone contraption. This pulls air into a liquid filled tube, trapping DNA fragments. This then allows for DNA extraction, amplification, and sequencing. This method is particularly efficient with insect species, which is significant because insects are the most diverse group of organisms on the planet. This article stresses how species identification is very important for conservation efforts. 

    I find this article to be incredibly interesting. As someone who actively studies insects, I feel as though this new method is far more efficient when it comes to insect identification and the identification of new insect species. it would also in theory utilize less resources, as now individuals studying the insects won't have to spend as much time in the field, therefore reducing the need for long term camping, and other resource use in the field. I can foresee some potential problems, however this is a fantastic starting point, and feels almost like the work of science fiction. I cannot wait to see where this research goes.

(Pictured is an example of a liquid cyclone separator)

How Bumble Bees Get Their Iconic Stripes

 

A recent study published by researchers at Penn State have found the genetic pathways that give bumble bees their signature look. Although many people associate black and yellow with those in the Bombus genus, there are at least 250 species across the world. Across these 250 species, there are an estimated 400 different color patterns that include blacks, whites, oranges, reds, and yellows to warn predators to stay away. Previously, these researchers explained that a major developmental gene, called a Hox gene, activates a "complex set of downstream genes" that drive the pigmentation changes. But they couldn't quite nail down how the change in the Hox gene led to pigment changes.

To figure this out, they looked at which genes were being targeted by the Hox gene. What they found was that by targeting the next major developmental gene, several melanin genes could be altered to reinforce the color traits. Their work also contributed the understanding of genes involved in making the red pigment called pheomelanin. Once thought to only occur in vertebrates (and in humans with red hair!), it was recently found in insects as well. By understanding how these bumble bee pigmentation genes develop, more research can be done on their diversification and evolution.

How Did Insects Get Their Wings?

Insects were the first organisms on the planet to have the ability to exploit particular environments to aid in their survival. It has been a mystery on to how these creatures developed their ability to fly and there has long been two hypothesis onto how wings came about. The "tergal hypothesis," suggests that the wings developed from the top of the insect body wall and formed gliding membranes while the, "pleural hypothesis," suggests that wings developed from ancient leg segments that originally merged with the body before ending up on the back. Now with the advancing developments in evolutionary biology, researchers are now suggesting a, "dual origin," hypothesis where wings fused from two separate tissues: the dorsal body wall and leg segments.

Dr. Tomoyasu and David Linz, two researchers, recently published in the National Academy of Sciences, were able to genetically engineer beetle larvae with an additional pair of wings on their abdomens. By injecting green fluorescent proteins into beetle larvae they were able to mark genes that expressed wing development. With these particular genes exploited, the researchers were then able to develop larvae with an additional set of wings on their abdomen. This result may suggest that insects may have originally had three sets of wings and lost a pair due to the possible loss in aerodynamics throughout natural selection. However, this data is just a fraction on what is needed to confirm how insects truly gained their ability to fly.

Article: https://www.nytimes.com/2018/03/26/science/insect-wing-evolution.html
Original Paper: http://www.pnas.org/content/early/2018/01/08/1711128115

The New Batch of Cicada

    A Cicada is an insect which is one and a half inches long, with red eyes and orange veins in their wings. These insects buzz, males in particular, by their tymbals, the corrugated exoskeleton on their torso that they contract and release.

    After a 17-year wait to mate, next brood of cicadas will start to emerge next month in parts of five states. These states are Western Maryland, eastern Ohio, southwestern Pennsylvania, northwestern Virginia and most of West Virginia are expected to see the rise of the Brood V. There are six species of cicada, three with a 17-year cycle and three with a 13-year cycle. Cicada spend 17 years underground, where they anticipate an uncertain indicator for emergence. The indicators are; a combination of soil temperatures reaching 64 degrees and light rain seems to trigger their arrival.  The problem of course, is that lots of cicadas get eaten anyway, this is fine as long as some of them survive to reproduce. That's why it's beneficial for the brood to emerge all at once, instead of in small groups. Cicadas with genes that make them emerge a little earlier or later than the pack would be spotted and eaten right away. The 13- and 17- year breeds, on the other hand, had less contact with other broods and stayed pure. The more that emerge at the exact same time, the more of them survive to mate. Stragglers and early birds were eliminated, along with their genes. Over thousands of years, evolution enhanced these broods to emerge in huge numbers, at precisely the same time, when few other cicadas threaten to dilute their gene pool.
These insects are very interesting. They live underground for most of there live then reemerge about 17 years later to start the cycle all over again. Having a gene regulate when they emerge is also a plus, but other factors come into play at this point but it still helps.

Centipedes get genome sequenced, reveal secrets of arthropod evolution

The genome of centipedes have been sequenced for the first time. Arthropods are underrepresented in terms of which organisms get sequenced. Professors at the Hebrew University of Jerusalem postulate that the centipede's genome tells us how arthropods made the sea-to-land transition.

It turns out that insects and centipedes independently evolved mechanisms for life on land. Centipedes do not have the gene for air-sniffing that insects do, so it sought elsewhere in its genetic arenal for a solution--at a locus that insects lack.

Link