green fluorescent protein

She’ll Feel A Fool, All Right, In About Another Week

The human female’s team at work has been scrambling busily, trying to turn in-person  classes into online classes.  The lectures have not been too difficult, but turning the labs into online experiences has been more challenging.  For the Heredity unit, the students usually observe crosses of  various mutant strains of Arabidopsis.   Normal seedlings have hairy leaves:

seedling with hairs

…but some of the mutants are bald.

Regular seedlings behave like proper plants, but some of the “special” ones are trans-genic–they’ve been gifted with the DNA that makes them produce a protein that glows an eerie green under blue light.

f1-hybrids-gfp1 x gl1

If they don’t have the glowy gene, they don’t show up at all under blue light–they’re just dark shapes:

homozygous gl1-no gfp

Since there isn’t a way for the students to have a petri dish of seedlings to look at, the human female had the bright idea to make sets of virtual seedlings.  She came up with little images of hairy and bald plants, and has been making spreads of what they’d look like in regular and blue light.

It’s very painstaking work.  She had to wrestle all the inheritance patterns and do the math to figure out how many seedlings should be hairy and glowy, how many hairy and not-glowy, how many bald and glowy, and how many bald and not glowy.  Then she had to divide up the hundreds of fictitious seedlings into twelve sets such that the students can only figure out the inheritance patterns if they score their seedlings their arrays and then pool their data with folks who have the other sets.  Each set has to be laid out exactly the same way in the visible light view and the blue light view so that the plants can be scored accurately.

It involves manipulating layers and layers of images.

She’s stepped away from her desk for a moment.  Let’s just scoot some of these little plants around, shall we?  (I don’t need to use a mouse–I have magic!)


Let’s see….I’ll take out two of the hairy/glowy ones and substitute a hairy/not glowy and a bald/glowy.   And I’ll shuffle them around in the blue-light view…  And I’ll make set G a duplicate of set B…  And then I’ll re-label set J as set number 7

And then I’ll throw in another mutation that makes them grow upside down, and…

…and then I’ll fix it so that her original files show on her computer screen, but the changed ones will go up on the server for the teaching assistants to give to the students.

I will not get to call her April Fool today, but next week, when the assignment is given out and the frantic phone calls, texts, and zoom sessions begin, the tears and wailing of the human female will be very sweet indeed.

I can wait.

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Sigyn Is In Love

Remember all the fuss with the power tools and racks and seeds?  It has all come to fruition.

The seeds came through their cold nap very well, and the students were able to plate up their seeds.  Well, mostly able.  Despite being instructed to pipette their seeds into a straight line on the Murashige and Skoog medium, some of the kiddos were guided by a certain Jotun who shall remain nameless and just plopped all of their seeds in the center of the agar.  Others, in a demonstration of obtuseness which will live in infamy, carefully pipetted all of their seeds onto the lid of the petri dish.

Still, enough of the little geniuses did it near enough to correctly for the plates, after two weeks in a growth chamber, to be worth looking at.

arapidopsis seedlings2

Sigyn thinks they are adorable and wants to hug them.


The students are using them to study heredity.  One of the parental lines is “wild type”.  When viewed through special glasses under a blue light, the little plants don’t fluoresce and just look like dark shapes.  The only brightness is where the light source is bouncing off the background.


The other parental type, however, has been Meddled With and gifted with a gene originally found in jellyfish.  The plants produce green fluorescent protein (gfp) in their cells.  When viewed with the fancy glasses under blue light, the plants fluoresce–they appear green and are clearly visible– not just shadows.

arapidopsis glow

Theoretically, the gene for fluorescence is supposed to be dominant.  Let’s look at the F1 plants, the hybrids between glowy and not glowy.  All of these seedlings have one copy of the glowy gene.


Great Mendel’s peapods!  All glowy!  Our hypothesis is correct!

Further observation of seedlings that are the result of crossing this F1 generation with itself shows that glowiness is inherited in a 3 to 1 ratio over non-glowiness, thus re-confirming that the gene for green fluorescent protein production is, in fact, dominant.

That green glowiness is a neat trick, I must say.  And yes, Sigyn, the little seedlings are cute.  But let us bring science to bear on the real question raised by this little experiment: What would it take to get this gfp into me so that I can glow green in the dark?

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