Category Archives: 04 Genetics
“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.
Genetic Engineering & Biotechnology Update
Here is the updated presentation for 4.4 Genetic Engineering and Biotechnology. There are some new slides and clearer explanations, as well as a new visual identity. It should also be downloadable as a pptx file.
For many more resources go to the page for 4.4 Genetic Engineering and Biotechnology.
Are we ready for neo-evolution?
An entertaining and informative TED talk by medical ethicist Harvey Fineberg on the future of human evolution and the ethics surrounding the decisions that we may soon be able to make regarding our children and our health. With strong links to the Human Genome Project, evolution, ethics, genetic engineering, stem cells and TOK, this is a great video to watch and stimulate discussion and thought in the Genetics unit.
What do you think?
DrosophiLab – Genetics Simulator
- Drosophila buscki
DrosophiLab is a brilliant, free and downloadable piece of software that allows students and teachers to edit fruit flies and carry out crosses. The teacher can use the chromosome editor to set up parent flies of any genotype and there are 20 genes and traits represented, on four chromosomes. This allows for simple monohybrid crosses, sex-linkage, gene linkage and many other combinations – so the problems you set can be differentiated by level. There is also a password-protected teacher setting, to restrict students’ access to results tables and chromosome maps (so they have to work it out for themselves!).
Here are our class resources:
Protocol sheets: DrosophiLab HL, DrosophiLab SL (pdf)
Fly files in this folder: http://www.box.net/shared/dy326rb01d
Chi-Calc (Chi-squared calculator, .xlsx)
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How to catch and observe Drosophila:
Catch Your Own Drosophila, from Access Excellence (lots of resources there)
And this is how you tell the sexes apart:
When trying to observe the flies for real, think about the following questions:
- How are you ensuring ethical treatment of the animals?
- How long would it take to determine the phenotypes of the number of flies you have set for your investigations?
- What difficulties do you encounter when observing the flies?
- What are the limitations or sources of error that might affect the reliability of your results?
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Why are fruit flies so important in science?
Science loves fruit flies, and there was even a fruit fly Nobel awarded in 1995 for studies in embryonic development. This links neatly to the assessment statements regarding the differentiation of cells through expression of different genes.
- Fly!
Fruit fly cells are relatively easily observed, and Drosophila makes for an ideal model organism for Mendelian genetics as it has a short life cycle, reproduces quickly and is easily phenotyped.
There is a biography of fruit flies called Fly: An Experimental Life, by Martin Brookes, and you can find out more about the Drosophila genome at http://www.fruitfly.org/.
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Image sources:
Drosophila buscki from Journal of Endocrinology
Fruit fly graphic and DrosophiLab banner from DrosophiLab
