Biology for Writers: Some Awesome Genetics Techniques I Use in the Lab

Good morning, everyone! Welcome to the first Biology for Writers post of the new year! Today, I wanted to talk about some common techniques used in genetics and molecular biology, particularly those I use in the lab, since those are what I’m most familiar with. As a result, the list will probably be skewed toward plant biology, but I will include other techniques I’m somewhat familiar with too. If you’re interested in a specific discipline or something you don’t see listed here, let me know in the comments, and I’ll be happy to tell you what I know or help you find some resources! Let’s get started!

DNA/RNA Extraction

Why? If you’re working in genetics or molecular biology, you often need to isolate a nucleic acid, be it DNA or RNA. These molecules are useful for learning about genes and the various proteins, including enzymes, they produce (more on this another time).

Why DNA vs. RNA? Well, the DNA contains a gene’s complete sequence, including introns (which are removed in the messenger RNA that determines the protein’s amino acid sequence) and regulatory sequences that control when the gene is turned on or off. So if you’re interested in the pure molecular genetics of an enzyme, you might extract DNA. DNA is also useful if you’re trying to sequence a new genome (the complete DNA of an organism); genomes are often useful for future research.

DNA
Image source

RNA, on the other hand, might be useful if you want to, say, produce a human protein in bacteria. To do this requires gene cloning, which is much easier with only the coding sequence (the part that actually codes for the protein–i.e. messenger RNA) rather than all the extra introns and “junk DNA” that comes along with a complete gene. So for things like genetic engineering, it’s better to extract RNA and back-convert it into DNA (more on this in a minute).

How? Extracting DNA/RNA is, in a nutshell, getting it out of the cells of your plant or bacteria or whatever organism you’re starting with, and separating it from the proteins, fatty acids, and other stuff that also belongs in a cell. (If extracting DNA, you also want to separate it from RNA, and vice versa.) The first thing to do, then, is to break open your cells. In plants, you usually start this by freezing your leaves in liquid nitrogen, which helps minimize molecular degradation, and grinding them up in a mortar and pestle. Then, a lysis (cell-opening) buffer is added to fully lyse the cells. (Buffers are solutions with a specific pH that “buffer” against big changes in acidity.) During this process, nucleases, which degrade DNA, are inhibited by the cold temperature from the liquid nitrogen. Other chemical inhibitors may be added as well.

Next, a series of centrifuging steps separates the DNA (in various liquid buffers) from proteins, lipids, and other cellular detritus (often in the form of a pellet at the bottom of the little test tube). DNA in the top liquid, or “supernatant,” is removed into several different tubes, until ultimately it is collected without the liquid on a little pad within a special tube. The DNA is then resuspended, or “eluted,” in super-sterile water (a small amount, like 150 microliters–a microliter is a millionth of a liter). This serves to make the DNA more concentrated. You can then measure how much DNA you extracted with an instrument called a fluorometer, and if you got enough DNA, you’re all set to go on to the next step!

Polymerase Chain Reaction

Why? Once you’ve extracted DNA, what do you do with it? If the answer is “isolate a gene,” your next step is polymerase chain reaction (PCR). PCR is an “amplification” technique that takes advantage of DNA’s structure to make many copies of your gene of interest. Then, you can move on to DNA sequencing, genetic engineering, or something else.

How? Let me first make a small digression into the basics of DNA’s structure. DNA is made up of four kinds of nitrogenous bases (let’s just call them A, T, C, and G) that join together in two long strands. The bases pair in a complementary manner to form that familiar double helix shape; A only pairs with T and C with G. When I talk about “DNA sequence,” I’m talking about the order of bases; AATCG is different from ATACG, for example. “Complementary sequence” refers to the sequence of bases on the other strand of the DNA; each DNA strand is the opposite of the other. For example, TTAGC is complementary (opposite) to AATCG. Got it? Great! Let’s go on to the technique.

PCR exploits DNA’s structure to make many, many copies of a gene or other sequence of interest. You can find a great fact sheet about PCR, including a helpful figure, here. Basically, if you know the sequence of your gene of interest, you can order custom short DNA molecules, called oligonucleotide primers (or just primers), of 15-25 base pairs each which are complementary to the ends of your gene. In a tiny little test tube, you mix together DNA, water, primers, and free nucleotides, and stick it all in a machine called a thermocycler, which can be programmed to heat and cool the tube for certain times. The heating profile basically does the PCR.

There are three basic steps to PCR. First, denature the DNA (separate the strands) by heating to about 95 Celsius. Next, drop the temperature to about 60 Celsius for annealing (of primers to DNA). The last step is extension (addition of new nucleotides to make a new DNA molecule), which happens at around 70 Celsius. Together, these steps make one cycle. PCR is usually repeated in about 36 cycles, which because there are more templates with each cycle, makes thousands of copies of the gene of interest, hence “DNA amplification.” PCR is a very useful technique and is indispensable in most genetics laboratories.

In fact, a form of PCR called reverse transcription-PCR (RT-PCR) is used to back-convert extracted RNA into complementary DNA (cDNA). RT-PCR uses primers that are specific for messenger RNAs, enabling the isolation and amplification of only the coding sequence of an organism’s genes. This is the next step from RNA extraction (see above).

Gel Electrophoresis

Why? This is a sort of confirmation technique. Once you have your extracted DNA/RNA or your PCR products, you want to make sure you did your previous techniques right, so you run an agarose gel. This helps you determine the size of your DNA fragments (or genomic DNA in the case of an extraction), so you know you can proceed with the next step in your research.

How? Gels are made from agarose, a compound found in seaweed, and buffer. You pour molten agarose into a rectangular mold with a comb stuck in, so when it hardens and you pull the comb out, you have a flat, rectangular Jell-O like surface with a line of wells at one end. After pouring buffer over the gel so it’s under the surface of the liquid, you mix your DNA/PCR product with a blue loading dye and put one sample into each well (called a “lane” once you’ve run the gel). You should always load a size standard, called a “ladder,” into one lane, and it’s good to run a positive control (you know the result will be what you want) and negative control (you know the result will be the opposite of what you want), so that if something’s wrong with your samples but not the controls, you know it’s the samples themselves, not your PCR.

Once you’ve loaded all your samples, the next step is to turn on the electric current and let the gel run. Because DNA has a slight negative charge, it will migrate toward the positive end of the gel (away from the wells in which you loaded it). As it moves, it will bump into all sorts of molecules within the gel, i.e., the gel itself will get in the way of the DNA’s movement. This allows for size separation of DNA fragments; smaller fragments will bump into the gel less and therefore move a greater distance in the same time. When you look at the gel under ultraviolet light, you see bright “bands” that indicate where the DNA is; the closer to the wells, the longer the DNA fragment. Comparing these bands to the ladder size standard (which shows up as many bands of known sizes) allows you to identify the size of your PCR product, so you can tell whether you got the right gene. This makes gel electrophoresis an immensely useful technique.

 

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Your Questions Answered, Part 2: General Biotechnology

Hi, everyone! Today I have Part 2 of a genetics/biotechnology/general life science post for you. You can check out Part 1 here. Again, thanks to H. Halverstadt for asking these fantastic questions! Let’s get right to it:

How do you think CRISPR and the gene drive will change the future of genetic engineering?

I am of the opinion that CRISPR is one of the most revolutionary advances in biotechnology of our time. The precision with which genes can be edited due to the specificity of the system is just incredible. I would certainly predict that its popularity (with scientists, not necessarily with the general public, especially the uninformed) will soar in the future, although at least for a short time, “conventional” genetic engineering will still be practiced. But given public outcry about GMOs (even if not warranted—a topic for another time), the ability to improve an organism without bringing in genes from another organism could be more popular and, indeed, simply easier, with fewer steps required.

The gene drive is more specific; I think it has a lot fewer potential applications than CRISPR. Whereas CRISPR can be used with most any current genetic engineering application, I really can’t think of an application for the gene drive that is really different from its current uses, combating insect-vector diseases and pesticide/herbicide resistance. They might try to tackle antibiotic resistance with it next, but I don’t think it will have broad-based applications after that. I would predict that CRISPR will be by far the more influential technique in future.

What gradual, irreversible changes to the human genome might happen?

My best idea is that, according to the principles of natural selection, any beneficial-to-survival changes made to a majority of people by genetic engineering (and propagated through the germ line) could eventually become fixed in the population. I’m going to stop there, since I don’t have quite the human or population genetics knowledge to go on.

Can you see cells from certain people being in high demand? What kind of people?

This is a very interesting question. First, instead of cells, I think we’d be talking about DNA sequences; why bother taking the whole cell if you can get just the DNA you want? I also assume here that the question is asking about acquiring copies of someone else’s DNA for non-gene-therapy genetic enhancement. In this case, I expect that genes from athletic people (there are some known genes related to athleticism—I know of one specific case in which a certain allele of one gene is associated with endurance running) and intelligent people (if such genes could be identified—to my knowledge there are none currently) might be popular for making “designer babies” and so forth.

What laws do you think might be passed to regulate genetic engineering?

I’m not as knowledgeable about the legal side of biotech, but currently, I know labeling laws for GMO foods are a big deal. A quick search revealed to me that GMOs are put through testing processes by a few federal agencies before being put on the market to determine their safety. It’s conceivable that a law prohibiting non-gene-therapy engineering of humans could be passed, although presumably not in the kind of society most sci-fi/dystopian writers who read this will be interested in. Besides that, I apologize, but I can’t come up with much.

Is inter-species gene editing something that is possible for humans?

Technically, yes. Ethically, it’s complicated. Personally, I don’t see this as acceptable, but I’m sure some bioethicist out there could make the case that improving human welfare by adding nonhuman genes would be worth the (hypothetical) cost in our humanity.  (A technical note: this seems to me to be less gene editing, and more transgenic expression. Gene editing is messing with a gene that’s already there; transgenics are organisms containing genes from other species.)

Do you see genetic engineering ever being something smart high school students can do in their kitchen?

Absolutely. In fact, this kind of thing is happening today among a DIY biologist or “biohacker” movement that believes science shouldn’t be for academia alone. So far, though, they’re not that scary; national and worldwide organizations like DIY Bio (https://diybio.org/) have been good about organizing events regarding safety and bioethics. It’s not being done to humans, or even vertebrate animals as far as I can tell; there are still too many ethical issues in that area. But yes, as long as you can afford the reagents and equipment, you can genetically engineer a plant or a (nonpathogenic) microbe. I believe even CRISPR is currently accessible for DIY biologists (though it costs about $500—I’m sure the price will go down as it becomes an established part of biotech).

If inter-species gene editing is possible for humans, how about humans and a different category of animals, like birds? 

Again, absolutely; you could put a plant gene in a human cell if you wanted, or vice versa. And I’ve read about glow-in-the-dark animals being created by expressing a jellyfish gene.

Please comment on the feasibility of these fantastical forms of genetic engineering. Winged humans, mermaids, elves, centaurs, giants, dwarves, humans able to breathe lower oxygen air. Do you think any other traits would bleed through? (Like for example, if winged humans had eagle genes, would they have other eagle traits as well?)

First, let me say that “dwarves” already exist; we know them as “midgets.” There are a variety fo forms of dwarfism, some dominant, some recessive, but none require genetic engineering. By “elves” I assume you mean basically humans with pointed ears. I expect this would most easily be done surgically.

As for “giants,” height is an extremely complex trait. It is quantitative, meaning that it follows a bell-curve distribution in the population, and there are currently thought to be about 700 genes that influence it. So engineering really tall people could be possible, but I suspect it would be inefficient in the incredible amount of effort it would take. Here is my source (http://time.com/4655634/genetics-height-tall-short/) for that, and I recommend you look up more detailed information on that trait if it’s something you’re interested in using in your story. I just don’t know enough about it to be of much help.

The others would be difficult, but theoretically doable in the far future given a masterful understanding of cellular physiology and probably lots of trial and error. For the humans with animal parts (winged, merpeople, centaurs), geneticists would need an almost perfectly complete understanding of development, which, once again, is incredibly complicated and controlled by many, many genes. It is possible that cells could be induced (“programmed”) to differentiate in such a way as to generate animal limbs on a human body, or to replace human limbs with animal ones, but this would also likely require detailed knowledge of the role of epigenetics in development, and complete knowledge of both human and animal development, which would simply take a very long time to achieve. And even then, it’s completely possible that scientists assembling and applying all this knowledge could miss something essential and make some terrible mistakes. Not to mention all the trial and error—what if a limb grew in the wrong place? etc. So, possible, but not probable to begin with, and would need to be masterfully executed.

The “bleeding through” of other traits mentioned in this question is, I would say, almost certainly not realistic. Giving someone wings will not automatically give them, say, sharp eyesight; that would be controlled by other genes (as well as environmental factors). It makes for interesting fiction, but as far as I know, there is no scientific basis for it.

As for the last one on the list, the pertinent process is cellular respiration. You would need to somehow increase the efficiency of this (again) complex process, which is only 39% efficient at capturing the energy in glucose into ATP (look up the basics of the process). I will say tentatively that this could be one of the more feasible things on this list, if only because cellular respiration is already fairly well understood (i.e. it’s not one of the great mysteries of our time) and preliminary studies could be carried out with bacterial or yeast cultures before progressing to human and mouse cultures, mouse trials, and finally human trials.

Here, to make a long answer longer, I want to make a general note about the approval process for human studies. I feel that the “evil scientist does unethical experiments on humans” trope is both overused and inaccurate. Every university, as far as I know, has an Institutional Review Board (IRB) that convenes solely for the purpose of evaluating and approving human-subject studies. This applies not only to clinical trials, but to interviews and surveys in psychology studies, and even to education studies that take class data and use it for research. Even if there is no perceptible risk at all, researchers are absolutely required to provide the subjects with knowledge about risks, so that they can be informed when they sign the form they must sign (even for a harmless survey!). This applies very much more to genetic engineering and so forth. Under this system, it’s very difficult to conduct an unethical study regarding human subjects, and unless social mores shifted in the future, it’s conceivable that the system will stay like this, making it difficult for any of these ideas to get off the ground, due to possible unforeseen consequences of the alterations.

If yes for the above, would reversal be possible, not just for the offspring but for the person in question? For example, if a winged human wanted to be a regular human again, would she be able to be one after extensive surgery and gene therapy?

I would say yes, although it’s completely a guess since I’m not a medical expert. The gene therapy might not even be necessary; though the genes might still be in the rest of her body, if they weren’t being expressed, she could be a “normal” human with nonhuman DNA, as long as her wings were removed. My bet is that the removal could be done with a surgical procedure (albeit complicated, probably, to remove the whole wing skeletal structure).

 

 

Karpechenko, Polyploidy, and Other Long Words

Greetings, everyone! It’s the second Saturday of the month already, and I am delighted to be here talking about one of my favorite science topics with you. As you may know, or may have guessed from reading my blog and noting the disproportionate amount of genetics posts, I am a genetics major, major DNA nerd, and plant biology minor. I’m going to bring all those things together in this post, so hold on to your hat and let’s have some fun!

As with many of my science posts, our topic today stems from a class I am taking (Evolutionary Genetics of Plants, in this case). My teacher told us a story, which I thought was cool, so I am now going to repeat it to you.

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The story was about this guy.

The guy in the picture above supplies the first of the long words in this post: his name, Georgii Dmitrievich Karpechenko. As you may have guessed, he was Russian. Specifically, he was a Russian botanist and plant cytologist (cell biologist) who did some interesting experiments with plant breeding. Let’s explore them.

Presumably, Karpechenko enjoyed both cabbages and radishes, or else he just wanted to contribute to improved agricultural productivity in his nation of limited farmland, or possibly both. Either way, he wanted to create a plant that produced a cabbage in the shoot and a radish in the root. The logical way to do this (his reasoning presumably went) was to cross a cabbage with a radish.

Here we have to back up a bit and get into some more long words. Cabbage and radish are different species, but not only that, they are in different genera (the first word of a scientific name); cabbage is Brassica oleracea and radish is Raphanus sativus. Usually, the definition of a species is “a population which is reproductively isolated (i.e. can’t breed) from others.” Of course, the only thing in science with no exceptions is that everything has an exception, and Karpechenko was indeed able to breed his cabbage and radish (for reasons we haven’t talked about in class yet) and produce a hybrid plant.

Well, unfortunately for Karpechenko, his hybrid didn’t look anything like either a cabbage or a radish. It was just a weed. Worse yet, it was a sterile weed; it produced seed pods, but no seeds. Fortunately for botany and genetics, though, Karpechenko didn’t give up on his experiments just yet. He kept observing his plants and noticed one day that a branch of one of them was producing seeds, even though the rest of this plant continued to be sterile. Furthermore, when he planted the seeds, they gave rise to fertile (if weedy) plants, and a new head-scratcher: how could this be?

Backing up again: The fertility of plants (or any organism, really) arises from a special cell division process called meiosis, which some may have learned about in high school biology. Most organisms are diploid, that is, they have two complete sets of chromosomes. For example, humans have 23 chromosomes in a set, and a total of 46 chromosomes in two sets. It works the same way for cabbage and radish; each has 9 chromosomes in a set, and 18 chromosomes total. This comes from reproductive biology; in any diploid organism, one of the sets of chromosomes comes from each parent. So in order to reproduce, plants (and animals, and fungi) have to produce haploid gametes, “sex cells” with only one set of chromosomes apiece. (In humans, we know them better as the sperm and the egg.) This is what meiosis is all about.

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A summary figure of meiosis. Note the homologous chromosomes separating into different cells; don’t worry about the different colors.

 

In order to reduce the chromosome set number, or “ploidy,” from diploid to haploid, chromosomes line up in matched (“homologous”) pairs and separate into two new cells (see the figure above). These cells then undergo further division to form gametes, the details of which we won’t worry about.

Now let’s think about Karpechenko’s sterile hybrid. This little weed had one set of chromosomes from cabbage and one set from radish, which enabled it to grow and function. However, when it came time for meiosis, it turned out that radish and cabbage chromosomes were different enough that they wouldn’t pair and divide into different cells, and no gametes were formed, which ultimately meant no seeds.

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Karpechenko’s experiments shown as seed pods. “Amphidiploid” is the same thing as tetraploid.

 

So what about that branch that became fertile? Well, it turns out that plants sometimes spontaneously undergo whole-genome duplications, in which, just as it sounds like, the entire genome of the plant is duplicated in the cell. (This happens routinely before cell division, but then it all divides into two cells. In whole-genome duplication, what happens is that the cell thinks it’s divided, but actually hasn’t, and now has four sets of chromosomes rather than two.) This happened in Karpechenko’s plant, in a branch precursor cell, and gave rise to a tetraploid branch, having four sets of chromosomes, two from radish and two from cabbage. Now, suddenly, all chromosomes had homologs to pair with in meiosis, and seeds could form.

Karpechenko had discovered polyploidy, the state of having more than two chromosome sets, which turns out to be a rather important phenomenon in plants. Besides generating greater genetic diversity, helpful to plant breeders, polyploidy results in more DNA, bigger nuclei, bigger cells, and eventually, bigger, more robust plants overall. It’s so useful that plant breeders sometimes induce polyploidy with chemicals to help in developing new varieties. Many important plants, such as wheat and canola, are polyploids.

What happened to Karpechenko himself? Well, in the early 20th century, the Soviet Union’s leadership was not big on genetics. In 1941, Karpechenko was arrested on a false charge and executed, but not before making a major contribution to botany and genetics.

What do you think? Have you heard of Karpechenko before? What about polyploidy? (Isn’t it cool?) Do you have any questions? Tell me in the comments!

Yakutian Horses and Pallas’s Cats: Adaptation to Extreme Environments

Good morning, all! It’s the second Saturday of the month, which means it’s time for a science post. This month, with winter approaching, I thought I would turn my attention to a couple of animals that are well adapted to cold environments: the Yakutian horse and the Pallas’s cat.

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The Yakutian horse is a breed of horse that lives in the Yakut region of Siberia; the Pallas’s cat is a species (Otocolobus manul) with a widespread range, from the Caspian Sea to northern India to China and Mongolia. Both these mammals show some common adaptations to cold environments, like small size (Yakutian horses are a bit smaller than most horses, and Pallas’s cats are only the size of a house cat) and long fur. According to the BBC, ancient woolly mammoths had similar adaptations, which enabled them to survive during the ice age.

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A new genomic study (reported by the same BBC article linked to above) has indicated that Yakutian horses evolved from Genghis Khan’s Mongolian horses in less than 800 years, basically the blink of an eye. Since they adapted to the harsh Siberian winters (with temperatures down to -94 degrees Fahrenheit), they’ve been indispensable to the Yakutian people, for food, clothing, and transportation.

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Pallas’s cats, in contrast, are wild. They live mostly in rocky areas at high altitudes (according to ARKive), and indeed, they’ve been found high up in the Himalayas where only snow leopards were thought to roam (see PBS’s “Nature: The Story of Cats”, episode 1). They’re active mostly at dawn and dusk, and hide in rock burrows the rest of the time to avoid predators. They’ve been known to inhabit burrows abandoned by other animals. To help them avoid predation, their fur changes color seasonally for camouflage.

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Here you can see just how fluffy the Pallas’s cat is.

 

That’s it for today! What do you think? Have you ever heard of these animals before? What do you think of them? Do you like winter as much as they do? Tell me in the comments!

My Life This October: In Which I See a Broadway Show, Catch a Cold, and Start a New Book

Hello, everyone! It’s the last Saturday of the month, which means I’m summarizing my month here for you. October has been a pretty full month for me, what with studying and numerous exams and being sick for much of the month (see second item in the title), so I’ll just give some of the highlights.

Near the beginning of the month, I got to go to Boston to see a Broadway show, stay at a fancy hotel, and have dinner in a fancy restaurant thanks to the McNair Scholars Program, which I am a part of at UNH. (If you’re a qualifying college student, you’re interested in doing research, and your school has this program, DO IT. I’m going to do it next summer and I can already tell it’s going to be awesome.) The whole weekend was really fun. I’d never experienced Boston like that before; I’ve been a lot with my family to visit museums and stuff, but it was a totally new experience going with a group of students for a night out. It was a blast. I saw my first ever Broadway show (Jersey Boys), and it was really good apart from lots of language and innuendo which I didn’t appreciate so much. As a writer, though, I thought it was very well written, and even the language and stuff was probably pretty accurate to the characters. I really enjoyed the music, too.

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Not what my playbill looked like, but it gives you some idea.

Dinner was also really good. It was a sort of stir-fry place where you get all your ingredients yourself (they have pasta and burgers, too), and then watch the chefs cook it up on one of those big round grills. UNH actually has one at one of their dining halls, but it was cool to see it on a larger scale. The ice cream was also fabulous. And staying overnight in the fancy hotel was a lot of fun, too.

Unfortunately, the month took a turn for the worse the next week, when I caught a nasty virus, the current “UNH Plague.” As I’m writing this, I’ve had it almost three weeks. It’s getting better now, but for a while it was really messing things up for me–I got my first ever 59 on an exam partially because of it. (Granted, I was above class average on this exam, because it was too long and everyone found it really hard, but still . . . a 59. . . .) But life goes on, viruses or not. And since I’m taking organic chemistry, the labels on medications are a lot more interesting now, even if I don’t actually fully understand what they say.

And somewhere near the beginning of this month (or the end of last month–I can’t remember which), I finished outlining as much as I felt I could at the moment and finally let myself jump into drafting Circle of Fire! It feels so, so good. First drafts are kind of my writing happy-place because that’s what I’ve done most and therefore what I do best. (I’ve gotten really good about letting my writing suck, haha.) It’s so nice to just have a creative release of words again. It’s also interesting to write in a different genre than usual; CoF is difficult to define as one genre, but I’d say it’s mostly thriller with fantasy elements. For age range, I might place it as older YA or cleaned-up NA, new adult, something I’ve never done before. I think that’s all I’ll tell you for now, but I’m going to keep doing Beautiful People posts for CoF characters, so if you’re interested, you can get little tidbits from those.

As far as life in general, school goes on. Week 10 of the semester has just finished, and we march on steadily toward finals week. I have eight more exams between now and then . . . I just have a lot of exams this semester (counting organic chem “quizzes” as exams, that is). I have determined that, for all my ranting about organic chemistry last month, physics is that much worse. Physics, even dumbed-down physics for life science students, is no joke (that’s the exam I got a 59 on. Yeah.). I’m glad I’m getting it over with this year. Genetics, though, has only gotten more interesting with the introduction of molecular genetics, which I love. And I’m thrilled to be taking advanced genetics classes starting in the spring. (The fun will soon begin. . . .) I’m still working in the lab, doing PCR and DNA extractions and to a lesser extent looking after baby seaweeds. So . . . yeah, that’s about it for the month. I’ll be back next week with a Story Starters post!

What about you; how has your month been? Are you in college or school? Have you been sick this month? (If you have, I feel your pain, believe me.) What classes are you taking? Have you done any writing this month? Started any new projects recently? Let me know in the comments!

Are Allergies Genetic? (Said the Science Nerd)

Yes, yes, on second Saturdays of the month, everything I say is from science-nerd mode, isn’t it? Specifically biology-nerd mode. I suppose that’s what happens when one is a genetics student.

Really, though, a couple of things influenced me to ask myself this question. Number one, I am a genetics student; therefore, I am curious about genetics. Number two, I have allergies, as does everyone else in my family. We’ve been sneezing off the hook for about three months now. I am mostly allergic to pollen (a real letdown for a plant lover), but people in my family are allergic to all sorts of things: horses, corn, sheep, hazelnuts, cats, you name it. So I wondered: are allergies genetic?

I asked Google that question, and it was kind enough to direct me to this interesting article, which not only answered my original question, but added more to the answer. It turns out that allergies are genetic, passed from parent to child. They are also sex-related; for example, girls are more predisposed to have allergies if their mothers also have allergies, and vice versa for boys.

Another article points out that there are different kinds of “allergic diseases,” including eczema and asthma as well as hay fever (pollen allergy). And, like anything else, allergies are influenced by environmental factors, including air pollution, chemicals, and types of animals and plants in the area, as well as by genetics. (See this abstract for more.)

Well, this turned out to be a short post. There are some quick facts about allergy genetics for you!

What do you think? Do you have allergies or something similar, like asthma? If so, do your family members have it, too, and have you ever wondered whether it was genetic? Tell me in the comments!