Eelgrass genetics!

Hello folks — so this is my first blog post, and rightly I’m going to introduce you to my project!

I venture far from the land of the developing vertebrates; in fact, I’m not even working with animals… my project is on the aquatic plant,Zostera marina, and its molecular genetics!

Z. marina is more commonly referred to as “eelgrass” — it forms meadows and estuaries in coastal lands across the world. These eelgrass beds provide shelter and protection for a variety of young fish and shellfish. Eelgrass is, therefore, immensely important to the marine environment of Maine and to the Maine fishing industry. Entire populations have collapsed, however, in Maine! And unfortunately, these have not been recovering, even with human efforts thus far. This particular decline appears to be due to destructive forces of the invasive European green crab ( great animated short about this here:

Throughout history, particular eelgrass populations have had their declines. Yet for such a common aquatic plant, these declines are no minor event: collapse has devastating effects on other species. Bay scallops used to be a major fishing industry in the mid-Atlantic United States (like in my home state, Maryland and its Chesapeake Bay!). Circa 1930s and into the 1960s, wasting disease wiped out the eelgrass, and subsequently the bay scallop. The bay scallop industry never made a substantial comeback. Chances are — and in theory, I could test this — those fried scallops at the Fisherman’s Platter in Commons are sea scallops. Okay, maybe it matters less what species gets deep-fried, but consider…

What species does Maine’s fishing industry have to lose? I can think of some big ones.

For the well being of Maine’s eelgrasses, and the planning of more successful restoration efforts, any contributions to decline must be explored. The focus of my research is six populations from around the Frenchman Bay and Mount Desert Island, of varying degrees of decline or susceptibility. In my project, I propose that the amount of genetic diversity of eelgrass populations in Maine — or lack of diversity — may determine whether a population is susceptible to decline. In my first semester, I obtained genomic DNA, after much trial and error. Plants are farstickierwith their DNA than animals and bacteria, and I had to devise a proper technique for extraction. This second semester, I am genotyping using markers called microsatellites.

Microsatellites are loci on the DNA that consist of short repeating sequences. Those short repeats are confusing to DNA polymerase during replication, and may lead to replication slippage. When this occurs, the loci may have an additional repeat unit. Those small differences in the length or size of loci are what my thesis rely on, to tell the difference between individuals and clones of eelgrass. Using primers that flank known loci, and are tagged with fluorescence, I amplified 400+ microsatellite fragments, 66 from each population. These lengths can be quantified very accurately using capillary gel electrophoresis (Chris Smith at MDIBL runs the machine and returns great sets of fluorescent peak data).

I am very excited this semester to be making the jump from wet lab to dry lab, because it is in the dry lab that I can finally see meaningful data. I could tell, almost immediately from the peak data, how long the loci were and the differences between two individual plants. A lot of stats and calculations await!