genetics – Page 5 – Montessori Muddle

Genetic testing: What it can do, and where we are.

“On average we found that each of us carries two or three mutations that could cause one of these severe childhood diseases.”
–Stephen Kingsmore, physician, Children’s Mercy Hospital in Greenfieldboyce (2010), New Genetic Test Screens Would-Be Parents.

NPR’s All Things Considered had two related articles on last night that deal with the specific topics we’re covering this week: genetic disease and recessive alleles.

The first one is about the latest in genetic screening technology, for determining if potential parents have recessive alleles that could combine to produce children with genetic diseases. Recent research has made this much easier.

The second touches on the ethical consequences of genetic screening. It could lead to an increase in abortion rates and leads us along the slippery slope of eugenics.

Beggars in Spain, by Nancy Kress — What if we engineered for intelligence?

This second story would make an interesting basis for a Socratic dialogue. As would, I think, the movie Gattica, which deals with the consequences of genetic screening and genetic customizations. I see it’s PG-13 so we may be able to screen it. Similarly, I may recommend Brian Stableford’s War Games to my eight graders who might like a military science fiction book that deals with genetic optimization. Alternatively, Nancy Kress’ Beggars in Spain might offer another interesting perspective on this issue.

DNA –> proteins

Learn.Genetics have some very nice animations and exercises that deal with DNA, genes and protein synthesis. At the moment, I’m finding the following particularly useful:

Instruction on how to extract DNA from anything, (I’m going to use this as a lab and perhaps to make pea soup too) and specifically, from people (inside of your cheek).
What makes a firefly glow animation. It’s a bit dense, but complements the transcribe and translate a gene exercise nicely.
The Observable Traits Slideshow identifies some of the same traits we look for in our exercises: dimples, handedness, etc. (they have a quick reference pdf.
There are a bunch of great traits activities, including family tree building, and traits bingo.

Recessive X’s are not so quiet

Punnet-square-gender-recessive — Punnet square for a gender conferred recessive trait.

Two X chromosomes (XX) makes women female. Men have an X and a Y, the latter of which is responsible for all the things that make them male. What we teach is that one of the X’s in the women’s XX’s dominates the other so that women’s physical characteristics (phenotype) is only determined by the dominant X. Recent research shows that’s not necessarily the case.

“Our study shows that the inactive X in women is not as silent as we thought,” said Laura Carrel, Ph.D., assistant professor of biochemistry and molecular biology, Penn State College of Medicine, Penn State Milton S. Hershey Medical Center. “The effects of these genes from the inactive X chromosome could explain some of the differences between men and women that aren’t attributable to sex hormones.” – From Penn State University, edited by Science Daily.

It’s a fascinating finding, but I don’t think I’ll go into it with the students except, in the very unlikely event, that a direct question comes up. At this point, simpler is better.

Jurassic Park: Web of Issues

Well we watched Jurassic Park last night and concluded it with a discussion about the issues underlying the movie, the same way we’ve been studying analyzing the issues underlying texts. Discrimination based on race and obesity came up first (the fat guy and the black people “always” die), but I was able to coax a bit of discussion about the role and responsibility of science and scientists. Our discussion is summarized in the graphic organizer above, but there are many more subtexts to the story that we did not have time to explore.

I like both the movie and the book because, like most good science fiction, they explore some interesting issues that relate quite nicely to the curriculum. Jurassic Park has a nice little introduction to DNA and gene sequencing that is tied to some the history of life on Earth. As works of art in their respective fields, however, I prefer the movie. The novel has a lot of wonderful detail, and the scientist in me loves the detail, but the characters are not as well drawn and the story seldom strays from its main thesis, scientific hubris. What it has to say about that issue is well expressed and well researched so it does capture the interest of the reader. (The follow-up book, “The Lost World”, sails adrift of the science, is logically incoherent and has a proportionate deterioration in the quality of the writing.) I do however recommend the original Jurassic Park book to my students as a personal novel.

Steven Spielberg makes a great movie, extracting empathetic performances from the actors. Since the book’s author, Michael Crichton, also wrote the screenplay, the movie stays true to the core issues in the text. I think its a great example of a successful, dare I say synergistic, collaboration.

Tomorrow, instead of retelling around the issues in writing, my students are going to try to do so in a skit. This could get interesting.

DNAi: History of genetics and manipulating DNA

DNA interactive is another great resource for studying the history of genetics and how we manipulate and use it today (recommended by the indispensable Anna Clarke). They have lesson plans and nice pages on the modern techniques used to work with DNA.

Image from the DNAi webpage on gel electrophoresis. Electrophoresis is a bit like chromatography which might make for a good demonstration.

I have not done much with genetic sequencing myself and I found the website interesting and informative. I have, however, written programs to get and work with the GenBank database, which is not that hard since they have some easy tools to work with. I would love to figure out how to get a sample sequenced and then run it through GenBank to identify it. It would so nicely integrate the curriculum, using a practical exercise to solve a problem (like what species are on the nature trail), while using the same tools and resources that scientists use, and tie wonderfully into the short stories in Mirable.

Teach.Genetics: Family trees

Dealing with genetic traits and family trees can be kind of tricky sometimes, particularly with early adolescents who are still learning about personal boundaries and have the potential for sharing too much information. One alternative to delving too deeply into personal family histories is to stress the less invasive traits. Anna Clark has had some success (and the students liked it) using the Handy Family Tree, from the University of Utah’s Teach.Genetics website.

John Wyndham's The Crysalids. (via Powell's Books).

I also discuss some of the thornier issues when we do the John Wyndham book, The Chrysalids. It can be an uncomfortable book, but has the emotional separation of fiction.

Teach.Genetics is a great resource. They have a number of “Teach and Go” exercises like this one, and some interesting interactive applications. I’ll post more as I browse more through their website.

Montessori Science Fiction

One of my favorite books that ties in with the study of the life sciences is Janet Kagan’s Mirable. It’s a series of stories about colonists trying establish themselves on a new world. Because of an accident on the trip over from Earth, the plants and animals they try bring with them (or propagate from their recorded DNA sequences) tend to randomly, and all too frequently, produce offspring that are hybrids of all sorts of phylogenetically unrelated organisms. The hybrids then produce other hybrids until, eventually, they produce another “Earth-authentic” species. This was supposed to be a feature to add redundancy to their gene banks. The impetus for the stories comes from the fact that some of the hybrids are unexpected and quite interesting, like the kangaroo-rex.

k-rex2 — M. A. Buss' model of the kangaroo-rex. Note the sharp pointy teeth and claws.

Kagan writes a good story, entertaining, light hearted and easily accessible to early adolescents, but I particularly like her model of education on the new world. Since they need as much genetic diversity as possible, even people who don’t want to raise children need to have them. So kids are sent to live at a boarding school that’s really a hotel, which they run. Sounds a lot like Montessori’s Erdkinder.

The kids get training and regular visits from experts in a variety of fields. They get to help of the protagonist with her projects by tracking animals in the field and running genetic sequences through their equivalent of GenBank.

The best science fiction provides interesting models of society. Mirable, I believe, is a model of a society designed around the ideas of Peace Education. The Montessori spirit runs throughout the stories not just in the education system, but in the way characters interact one another, even in times of conflict.

I’m an unabashed advocate for using science fiction in the classroom because it delves into such wide ranging parts of the curriculum, Natural World, Social World, Language and, in this case, Peace Education. Of course the stories have to be chosen well. Mirable is one of perhaps only two books (the other is The Chrysalids by John Wyndham) that I use when we study the life sciences.