Genetic analysis: my results and my reality

A few months ago, it was National DNA Day or something like that, and one of the genetics analysis companies had a sale on their analysis kits, offering a full panel of testing for only $100. Giddy with the excitement of saving almost $1000 on something I’d long been interested in doing, I signed on, ordering one kit each for my husband (a.k.a. “The Viking”) and me. Soon, we found ourselves spending a romantic evening spitting into vials and arguing about whether or not we’d shaken them long enough before packaging them.

The company promised results in six weeks, but they came much faster than that, in about three weeks. Much to my relief, I learned that neither of us carries markers for cystic fibrosis and that I lack either of the two main mutations related to breast cancer. Those basic findings out of the way, things then got more complex and more interesting.

How it works

First, a bit of background. These tests involve sequencing of specific regions to look for very small changes, a single nucleotide, in the DNA. If there is a study that has linked a specific mutation to a change in the average risk for a specific disorder or trait, then the company notes that. The more data there are supporting that link, the stronger the company indicates the finding is. Thus, four gold stars in their nomenclature means, “This is pretty well supported,” while three or fewer slate stars means, “There are some data for this but not a lot,” or “The findings so far are inconsistent.”

Vikings and Ireland

The Viking is a private person, so I can’t elaborate on his findings here except to say that (a) he is extraordinarily healthy in general and (b) what we thought was a German Y chromosome seems instead to be strictly Irish and associated with some Irish king known as Niall of the Nine Hostages. Why hostages and why nine, I do not know. But it did sort of rearrange our entire perception of his Y chromosome and those of our three sons to find this out. For the record, it matches exactly what we learned from participating in the National Geographic Genographic project. I’d ask the Viking if he were feeling a wee bit o’ the leprachaun, but given his somewhat daunting height and still Viking-ish overall demeanor (that would be thanks to his Scandinavian mother), I’m thinking he doesn’t. Lord of the Dance, he is not.

Markers that indicate an increased risk for me

I have an increased risk of…duh

Looking at the chart to the left (it’s clickable), you can see where I earned myself quite a few four gold stars, but the ones that seem most relevant are those with a 2x or greater increased risk: lupus, celiac disease, and glaucoma. The first two do not surprise me, given my family’s history of autoimmune disorders.

If you focus on a list like this too long, you can start to get a serious case of hypochondria, worrying that you’re gonna get all of these things thanks to those glaring golden stars. But to put it into context, for the lupus–for which my risk is 2.68 times higher than a regular gal’s–that still leaves me in the population in which 0.66 persons out of every 100 will develop this disorder. Compare that to the 0.25 out of every 100 in the regular-gal population, and it doesn’t strike me as that daunting.

Some of those other things on there? Well, let’s just say they’re close. My risk of thyroid cancer might be raised…but I no longer have a thyroid. Hypertension risk is increased–and I have stage 2 hypertension. Gallstones, gout, alcholism, asthma…based on family history, it’s no surprise to me to see some mixed or clear risk involved with these, although I have none of them. Does that mean that someone else with these increased risks will have related real-life findings? No. It only means that you’re at a bit more risk. It’s like riding a motorcycle vs. driving a car. The former carries more risk of a fatal wreck, but that doesn’t mean you’re absolutely gonna die on it if you ride it.

Disorders for which my risk is allegedly decreased

I have a decreased risk of...

None of my decreased risk findings are very eye catching in terms of actual drop in risk except for Type II diabetes (now where is my bag of sugar?). As I have been under evaluation for multiple sclerosis and have a family member with it, it’s interesting to see that my risk for it, based on existing studies and known polymorphisms, is decreased. And even though I know that much of this is largely speculative and based on little firm data, it’s still sort of comforting to see “decreased risk” and things like “melanoma” in the same group.

Don’t make my brown eyes blue!

And they didn’t. They nailed the eye color and other trait-related analysis, such as level of curl to the hair, earwax type, alcohol flush reaction, lactose intolerance (unlikely), and muscle performance (I am not nor have I ever been a sprinter). And even though I do not have red hair, they reported that I had a good chance of it, also true given family history. I am not resistant to malaria but allegedly resistant to norovirus. I wish someone had informed my genes of that in 2003 when I was stricken with a horrible case of it.

Ancestral homeland

Yep. They nailed this one. One hundred percent European mutt. Mitochondria similar to…Jesse James…part of a haplogroup that originated in the Near East about 45,000 years ago then traveled to Ethiopia and Egypt and from there, presumably, into Europe. It’s a pretty well traveled haplotype and happens to match exactly with the one identified by the National Geographic Genographic project. When it comes to haplotypes, we’re batting 1000.

In summary

Some of these findings are reliable, such as the absence of the standard breast cancer mutations or the presence of certain mutations related to autoimmune disorders, while other findings are iffy. The company duly notes their iffiness  in the reports, along with the associated citations, polymorphisms, and level of risk identified in each study. They don’t promise to tell you that your ancestors lived in a castle 400 years ago or hailed from Ghana. From this company, at any rate, the results are precise and precisely documented, and as I noted, pretty damned accurate. And they’re careful to be a clear as possible about what “increased risk” or “decreased risk” really means.

It’s fascinating to me that a little bit of my spit can be so informative, even down to my eye color, hair curl, and tendency to hypertension, and I’ve noted that just in the days since we received our results, they’ve continually updated as new data have come in. Would I be so excited had I paid $1100 for this instead of $200? As with any consideration of the changes in risk these analyses identified, that answer would require context. Am I a millionaire? Or just a poor science writer? Perhaps my genes will tell.

Going to Hawaii? Watch out for the flesh-eating caterpillars

Flesh-eating caterpillars lurk in Hawaii’s rainforests

Islands can produce some of the strangest evolutionary novelties on the planet. Island-living elephants shrink to tiny sizes, while tortoises grow gigantic. The fate of species on islands is its own specialized study because the only way species can arrive on an island is over the water. Scientists, in the study of island biogeography, focus on how plants, animals, and microbiota end up on the islands where they occur.

What happens after they arrive is apparently anybody’s guess. Islands are unusual because they can lack the stiff competition of mainland ecosystems. Common factors in our daily lives, like ants, can be completely lacking. Because so many pieces of an ecological puzzle are missing on an island, niches remain open for the organisms that do arrive and get a foothold. Animals and plants end up doing things on islands that their kindred are not known to do anywhere else in the world. A recently discovered example is a caterpillar that has broken all the rules of caterpillardom. It eats meat. It hunts its prey. It uses its silk as a weapon. It deliberately camouflages itself with non-caterpillar components. And it’s a brutal killer.

Like a wolf that dives for clams

This particular capterpillar and its four just-discovered relatives reside on one of the most isolated island chains in the world, the Hawaiian archipelago. These islands are well known for evolutionary novelties, and these new species of the genus Hyposmocoma are no different. Well, actually, they’re very different. One scientist has said that discovering the behavior of these larval moths is like discovering a wolf species that dives for clams.

This caterpillar, a tiny, brutal, sneaky killer, creeps up on its prey, an unsuspecting snail resting on a leaf in the Hawaiian rainforest. The caterpillar itself is bound in silk, and it proceeds to spend almost a half hour anchoring the hapless snail to the leaf with more silk. The silk, made of gelatinous proteins, pins the snail by its shell as tightly as a spider wraps its threads around prey.

Once the caterpillar has immobilized its target, preventing the snail from escaping through a fall off of the leaf, the nascent moth emerges from its own silk casing. The snail retreats into its shell, and the caterpillar follows, beginning to feed on the trapped snail, starting with the head. It literally eats the snail alive.

This behavior is extraordinarily unusual for a caterpillar, the juvenile form of moths and butterflies. The vast majority of caterpillar species are vegetarian; of the 150,000 known species, only 200 have been identified as flesh eaters and predators. These few do not use their silks to trap their food, and they don’t eat snails, which are mollusks, targeting instead soft-bodied insects.

Caterpillar divers and adaptive radiation

But the genus Hyposmocoma is known for its diversity. Some of its members dive underwater for food. The interesting thing about the snail-eating caterpillars is that they seem to have radiated through almost all of the Hawaiian islands. The first species was identified on Maui, but since its discovery, researchers have found species on most of the other islands. Evolutionary biologists are intrigued by the many novel aspects of this caterpillar’s life history because it is so unusual for this many unique factors—novel food source, novel hunting technique, novel eating technique—to have evolved in the same species.

Wearing the spoils of capture as camouflage

One other unique thing about this caterpillar’s approach to dinner is its use of decoration. Once the mollusk-eating caterpillar has spent the day dining on escargot, it will attach the snail’s empty shell to its silken casing, along with bits of lichen and other materials, in an apparent attempt to camouflage itself.

Follow

Get every new post delivered to your Inbox.

%d bloggers like this: