This tiny jellyfish known as Polyorchis pencillatus is known as red-eyed jellyfish. Its a number of eyes, known as ocelli, could be seen on the base of the tentacles and comprise light-sensing cells and purple pigment. Credit score: Anna Klompen
Some jellyfish have easy eyes; some have advanced ones. Different jellyfish haven't any eyes in any respect. Certainly, current analysis has proven jellyfish eyes in several species have developed individually and independently many instances in several methods over many millennia, making them a perfect mannequin to raised perceive how the trait expresses itself genetically.
Now, a workforce of researchers that features Paulyn Cartwright, professor of ecology & evolutionary biology on the College of Kansas; Maria Pia Miglietta of Texas A&M College, Galveston; and lead principal investigator Todd Oakley of the College of California, Santa Barbara, has acquired a grant from the Nationwide Science Basis to review how jellyfish-eye “convergence” — duplicated occasions within the historical past of life — offers a window on how evolution works at genetic, mobile and morphologic ranges.
The KU portion of the NSF grant totals $494,890.
“Eyes developed a number of instances independently throughout the jellyfish,” Cartwright mentioned. “We’ve identified for some time that there's not a single origin of eyes in all animals however have been stunned at what number of instances they developed independently in jellyfish.”
Now, Cartwright and her collaborators plan a scientific “deep dive” into evolutionary patterns to find whether or not jellyfish use the identical or totally different points of their genetic toolkit to construct eyes each single time that they've developed.
The researchers plan to reconstruct an in depth phylogenomic tree of Medusozoa (a clade within the Cnidaria phylum) to hint the evolutionary historical past of jellyfish eyes and use comparative transcriptomes and single-cell RNA sequencing to find out similarities and variations in genetic pathways of convergent eyes.
“Jellyfish are a very nice system for this, as a result of they've a variety of eyes, starting from easy clusters of light-sensing cells to very advanced eyes — camera-type eyes that may kind pictures and have a lens, a cornea and a retina — so superficially, they will look an identical to vertebrates,” Cartwright mentioned.
In her KU lab, she plans to research many species of jellyfish to find out all genes expressed in single cells of various jellyfish eyes and discover what’s shared amongst totally different situations of jellyfish and what’s modified of their fundamental genetic constructing blocks.
“Cells themselves have their very own traits, they usually’re actually an consequence of many, many various genes being expressed — so typically we'd miss an general sample by taking a look at particular person genes,” the KU researcher mentioned. “But when we have a look at all of the genes which are expressed on the cell and what that exact consequence is, that may give us a unique stage of data. That’s why it’s nice to take a look at all these totally different ranges and see what is analogous and what’s modified to actually assist us perceive this very sophisticated query. Jellyfish are a fantastic system to do that as a result of they’re so amenable to these kind of experiments. We will have a look at particular person genes and the way they’re expressed; we will look wholesale in any respect the genes which are expressed in these cells; after which we will see what is analogous on the morphological stage between these and what’s totally different.”
A part of the work below the brand new NSF grant will embrace journey to Panama, a hotspot of jellyfish biodiversity, to gather specimens. Cartwright and her colleagues will use the fruits of their analysis to assemble a extra detailed phylogenetic tree, or evolutionary historical past, of jellyfish.
“Jellyfish are very numerous — there’s a couple of thousand species,” Cartwright mentioned. “Uncovering their precise evolutionary historical past has been actually difficult partially as a result of a variety of this diversification occurred over half a billion years in the past. The opposite problem is to pattern these organisms. A lot of them reside in open-ocean environments within the deep sea, and a few of them are extremely small and exhausting to search out. So, we’re taking a look at historical divergence instances inside a various and difficult-to-sample group. This has been a problem that I’ve been engaged on for at the least the final 20 years of my profession, so we’re actually excited within the age of genomics as a result of getting extra information and with the ability to sequence extra genes and throwing extra DNA sequences at this drawback is anticipated to be very promising at resolving a few of these relationships amongst Cnidarians.”
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