A short (abbreviated) introduction to gene expression — how proteins are produced from DNA.
Semi-artificial Selection?
Just like drug resistant germs (we’ve discussed earlier), the rats are evolving.
“They’ve also mutated genetically and are bred to be immune to standard poisons.
“We have had to start using different methods such as trapping and gassing, which can be less effective and more costly.”
–Graham Chappell, from Rapid Pest Control in Newbury in Rowley (2012): Home counties demand stronger poison to deal with mutant ‘super rats’ in The Telegraph.
Homework or Not?
The Finnish and South Korean educational systems are ranked number one and two in the world, yet they’re at opposite ends of the homework assignment spectrum. Louis Menand elaborates:
Students [in Finland] are assigned virtually no homework; they don’t start school until age seven; and the school day is short.
[South Korean schools] are notorious for their backbreaking rigidity. Ninety per cent of primary-school students in South Korea study with private tutors after school, and South Korean teen-agers are reported to be the unhappiest in the developed world. Competition is so fierce that the government has cracked down on what are called private “crammer” schools, making it illegal for them to stay open after 10 P.M. (though some attempt to get around this by disguising themselves as libraries).
— Menand (2012): Today’s Assignment in The New Yorker.
via The Dish.
Empathy
Empathy is seeing the world through the eyes of others. Adolescents tend to look inward, not outward, but empathy is the basis of morality, so exposure to others and other points of view is an important element of their education. I find the following video interesting (much like the Bright Eyes video) because in its hints at so many hidden messages and meanings. It provokes thoughts about who these kids are, what is life like for them, and how do they see the world.
Note: David Brooks argues that while empathy orients one toward moral behavior, it’s really sacred moral codes that convert that orientation into action.
Genetics: Tracing the Gypsies back to India
A recent genetic study has confirmed that gypsies (Romani) probably originated in India. Dean Nelson summarizes.
Scientists from Hyderabad’s Centre for Cellular and Molecular Biology collaborated with colleagues in Estonia and Switzerland to compare more than 10,000 samples, including from members of 214 different Indian ethnic groups. They were analysed to match a South Asian Y chromosome type known as “haplogroup H1a1a-M82”, which passes down male bloodlines, with samples from Roma men in Europe.
While there were matches with samples from men throughout the Indian sub-continent, the closest match and the least genetic variation occurred with those from north-west India.
When the researchers overlaid the closest matches onto a genetic map of India, the highest density was in areas dominated by India’s “doma”, “scheduled tribes and castes” – the low caste dalits or untouchables who suffer widespread and generational discrimination and usually do society’s dirtiest jobs.
The researchers believe the descendants of today’s Roma gypsies in Europe began their westward exodus first to fight in wars in what is today Punjab between 1001 and 1026 on the promise of a promotion in caste status.
— Nelson, 2012: European Roma descended from Indian ‘untouchables’, genetic study shows in The Telegraph.
This type of genetic study looks at sections of the DNA sequence, specifically a certain group of genes that is slightly different in people from India compared to everyone else.
A gene is a section of DNA that does a certain job, such as producing a specific protein that results in a certain physical characteristic like eye color. Everyone has the gene for eye color, but some people have a version that gives blue eyes, while others might have a green eye version. The different versions of genes are called alleles, so you can say that some people have the allele for blue eyes while others have the green eye allele. Groups of alleles are passed on from parent to child, which is why children look like their parents, and why different ethnic groups from around the world look different from each other.
So if we take a group genes (call it a haplogroup) and compare the versions characteristic of Indians to those of Gypsies, we can see how similar the two groups are. This study (Gresham et al., 2001) found that Romani and Asians share 45% of the alleles within this haplogroup, which is pretty high. They also looked at another haplogroup in the mitochondrial DNA (mtDNA) that is only passed on from mothers to their children (it’s matrilineal) and found a 26% match.
Making the assumption that mutations in genes occur at a constant rate, the new study estimates that the Roma emigrated out of India somewhere around 1000 years ago.
The relatively recent ages determined for haplogroup VI-68 and M in this study suggest that the ethnogenesis of the Roma can be understood as a profound bottleneck event. Although identification of the parental population of the proto-Roma has to await better understanding of genetic diversity in the Indian subcontinent, our results suggest a limited number of related founders, compatible with a small group of migrants splitting from a distinct caste or tribal group.
–Gresham et al., 2001: Origins and Divergence of the Roma (Gypsies) in The American Journal of Human Genetics.
This is however, not the only evidence of an Indian origin. There are also significant similarities between the Romani and Indian languages that were noted long before. In fact, there is a fascinating, and my modern sensibilities, quite politically incorrect article on the topic of the origin of the Gypsies in the February, 1880 issue of Popular Science Monthly.
$10.09 per ton of Carbon Dioxide
… one metric ton of carbon dioxide is what’s produced by an average month of electricity use in a U.S. home.
— Troeh (2012): California’s first carbon auction launches pollution market on Marketplace.
California recently auctioned off a set of carbon emission permits as the start of an effort to reduce emissions of greenhouse gasses with an emissions trading system.
The first 23.1 million permits sold out at $10.09 per ton.
Eve Troeh discusses:
Reducing carbon dioxide emissions in the U.S.A.
Scott Tong has an interesting article in Marketplace about how the U.S. is reducing its carbon dioxide emissions through things like regulation of car fuel efficiency and light bulbs.
Building a Tree of Life (version 2)
I so liked how the tree of life turned out the last time I tried it, that I did it again this year with a significant improvement in the use of rubber bands.
Students chose organisms and then looked up their classification — Wikipedia quite reliable for this — then they wrote the names down on synchronized chips of colored paper. As usual, they preferentially chose charismatic, mammalian, megafauna, but there was also a squid, and for two people who did not come up with anything themselves, I assigned a plant (elm), and a bacteria (the one that causes strep throat).
The actual color pattern of the chips does not matter, but I used red for Domain, yellow for Kingdom, green for Phylum, pink for Class, red for Order, yellow for Family, green for Genus, and pink for species. The colors repeated, and I liked how that helped organize the pattern of the final result.
In class, using a pin-board, I used push pins to place homo sapiens on the board. I linked the push pins with rubber bands, which makes for a nicer, sharper pattern than using string, and is easier to do.
To get a nice pattern I then asked who had the closest relative to humans. It took a little effort to figure it out, but I decided to go with a degrees-of-separation metric. Basically, I asked them to count up the classification system to see how many levels they’d have to go to get to something their species shared with humans. The closest were at the Class level: mammals.
Then, starting with the students with the lowest separation distance, I had the students come up to the board and add their organism to the growing tree.
Later, during lunch, a student asked me what was the difference between bison and buffalo. I didn’t know, but another teacher pointed out that one was from North America and the other from Africa. So I asked two of my middle schoolers to look up the classification of american bison and water-buffalos, which we subsequently added to the tree, and which got me thinking about how we might use the rate of separation of the two continents to figure out how fast genetic variation develops.