Category Archives: 04 Genetics
Space Twins & Epigenetics
Mark and Scott Kelly at the Johnson Space Center, Houston Texas. Source: Wikimedia Commons.
Sign up for the Teach.Genetics mailing list from GSLC here.
The ever-wonderful Genetic Science Learning Center at the University of Utah sent this helpful email update to counter misconceptions around the Kelly Twins’ “Genetic Differences” as a result of Scott’s year on the International Space Station.
You may have seen the headlines about identical twin astronauts, Mark and Scott Kelly, now being “genetically different” after Scott spent a year in space while Mark remained on Earth. Yet much of the popular press has failed to explain that these differences are mostly epigenetic modifications leading to changes in gene expression. Or that several of the analyses were limited to circulating white blood cells and are thus mostly relevant to the immune system.
Here are some great resources they shared:
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Epigenetics on Learn.Genetics
The Epigenetics module on Learn.Genetics and Teach.Genetics explores how signals from the environment regulate gene expression, including an explanation of how differences in identical twins might arise
- Scott Kelley’s telomeres were elongated in space and shortened on Earth. Learn all about telomeres from this primer.
- The study also compared the microbiomes of the Kelly twins—which, it turns out, were quite different even before Scott Kelley traveled to space. Explore the Human Microbiome module on Learn.Genetics and Teach.Genetics.
Now go over and subscribe!
They have great resources for students at the Genetic Science Learning Center, and for educators at their new Teach.Genetics site. You can also follow them for Twitter updates here. Sign up for the Teach.Genetics mailing list from GSLC here.
Where do new genes come from?
Here’s a neat little TED-Ed Lesson by science writer Carl Zimmer (follow his blog, The Loom, on evolution).
30-Minute Inquiry: Base-substitution mutations
This has worked well (and been fun) as a topic review, way to make use of databases (ICT in IBBio requirement) and make connections as we.
Question: What do HBB, PAH, PKD1, NF1, CFTR, Opn1Mw and HEXA have in common?
Concepts: Structure vs Function; Universality & Diversity.
The set-up:
- Assign groups by handing out cards with the codes above (we had already studied HBB, so didn’t include it) and asking them to find each other.
- Give them the instructions – to produce a simple poster & 1-minute overview of their disorder, using the guidance in the image below.
- Go. Lots of discussion, lots of questioning. If students get stuck, they need to look it up, evaluate their sources and keep on going.
- Students will need to use the NCBI gene database to get going: http://www.ncbi.nlm.nih.gov/gene
Check they’re on the right track: HBB (sickle cell), PAH (PKU), PKD1 (polycystic kidney disease), NF1 (neurofibromatosis), CFTR (cystic fibrosis), Opn1Mw (medium-wave sensitive colour-blindness), HEXA (Tay-Sachs disease). They are all disorders causes by base-substitution mutations.
After 30 minutes:
- Groups present to the class what they have found.
- As the class sharing continues, ask questions based on connections:
- What similarities and differences do we see?
- What are the normal functions of these genes and how does this connect to our understanding of proteins, channels, pumps, etc.
“Changing Crops for a Changing Climate” Mark Lynas & a Nature Special on GMOs
Here is Mark Lynas at Cornell University, with his speech “Time to call out the anti-GMO conspiracy theory.” It runs almost half an hour, though he does have a transcript of the speech on his blog. The connections to IB Biology Genetics & Genetic Engineering here are obvious.
What should be noted for background is Lynas’ own story. In the 1990’s he was a prominent anti-GMO activist, but has recently apologised and is now on a mission to right the wrongs he feels he has done. It has not been easy, and has generated lots of controversy.
“Allowing anti-GMO activists to dictate policymaking on biotechnology is like putting homeopaths in charge of the health service, or asking anti-vaccine campaigners to take the lead in eradicating polio.”
Powerful and provocative stuff – and a great stimulus for discussion and debate. Lynas refers to a lot of studies, claims and organisations in this speech. Students could follow this up with finding out more about each of them.
We might never be able to get students to the absolute truth on GMOs – we may find it difficult ourselves – but it is useful to give some insight into just how delicate the balancing act can be and how cloudy the discussions of ethics in science can get. The issues around GMOs are complex: scientific, political, ethical, economical, environmental. They are far more complex than a couple of short assessment statements in a Biology syllabus can really do justice.
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Rise of the Superweeds. Click-through to the Nature Special.
Also recently, a very useful Nature special edition on GM Crops: the Promise & Reality. Look in for some in-depth articles and case-studies, including the true, the false and the still unknown on GM crops.
Nature articles often have presentations of data that can be used for data-based question practice (such as the one to the right – click through to see). Follow the patterns of the DBQ’s and make up your own questions based on different articles:
- Identify…
- Describe the trend in…
- Calculate the difference in…
- Compare…
- Suggest reasons for…
- Evaluate…
Inheritance: a short history of sex, genes and DNA
This week was the first episode of Dara O’Briain’s Science Club from the BBC. The theme: Genetics. Here’s their introductory animated clip, which gives a neat condensed history of sex, genes and DNA:
I’m looking forward to seeing the series!
Fruit Fly Development: Cell by Cell [Nature Video]
Drosophila melanogaster
Wow. Two papers published in Nature Methods have outlined a new technique which allows researchers to track development of embryos (in this case Drosophila melanogaster), in real time. By taking simulataneous multi-view microscopic images of the developing embryo, individual cells can be tracked in real time. The methods are described in more detail at Nature News here.
Have a look at the amazing results below, as a fruitfly embryo develops into a larva, ready to hatch. The two views are the dorsal (upper side) and ventral (lower side) view of the same embryo. See if you can pick a cell and watch its path of development.
Think about how this links to IB Biology topics of cell division, cell specialisation and embryonic development. How does a stem cell know what type of cell to become? If you look closely, there’s a scale bar in the bottom-right. Take a snapshot and calculate the actual length of the embryo.
For more reasons to love fruit flies, check out my mini-review of Fly: An Experimental Life by Martin Brookes.
Image source: Drosophila melanogaster, from Wikipedia.
Animal Development: We’re All Just Tubes! [CrashCourse Biology]
Another enterucational video from Crash Course Biology, which links nicely to section 5.5 Classification (and a wee bit on embryonic development). Check it out:
This is the kind of content that would be useful as a flipped lesson on TED-ED.
Drew Berry’s Animations of Unseeable Biology [TED Talk]
In 2011, Drew Berry’s animation of the role of breast stem cells won the Imagine Science Film Festival award for visual science (posted here). In this TED Talk, he explains how and why he and his team have put together these accurate representations of invisible cellular processes. The talk shows some examples of the animations, including a really great segment on mitosis and what is happening when spindle microtubules attach and contract.
For more excellent animations, visit the Walter and Elizabeth Hall Institute (WEHI) TV Channel: http://www.wehi.edu.au/education/wehitv/, or their YouTube channel.
The effective communication of Science is an Art.
How Epigenetics Works
Neil deGrasse Tyson presents this short PBS NOVA overview of how epigenetics determines the differences between gene expressions in identical twins, how epigenetic variations build up over time and how it affects us. A relatively new, but very interesting field of medicine and genetics, this is a good introduction.
Epigenetics is not directly mentioned in our syllabus, but does help us to connect the ideas of nature vs nurture, genetic variation and inheritance. To what extent does the nurture of our cellular environment (lifestyle) affect the genetic nature of who we are?
For some more really good resources on epigenetics, visit the brilliant Learn.Genetics site from Utah.
Thanks to Ed Yong for posting this on his weekly links roundup.
i-Biology 