Tag Archives: DNA

An Edited Google Doodle and a Genetics Mini-Mystery

Google’s Doodle on January 9 honored Har Gobind Khorana, a Nobel laureate whose work with DNA, RNA, and protein synthesis was seminal to deciphering the genetic code. Did anyone besides us (shout out to our own Eli Kosminsky!) notice that, midway through the day, the cartoon changed?

Google Doodle in the morning…

 

The same Doodle at night!

A comparison shows that the letters vanished from the paired strands draped across the doodle, leaving the flag-like bases letterless. A look at the letters depicted in the original doodle’s strands shows the letter “U,” for the base uracil, on both sides, making the drawing look like two paired strands of RNA. It’s the paired RNA strands that was the problem, we surmise. RNA, unlike DNA, comprises a single strand of nucleotide bases or “letters,” not a double strand (which, in the case of DNA, twists into the classic double-helix shape). By labeling both strands of the molecule with RNA letters, the doodle effectively depicted RNA as an extended double-stranded molecule, which is incorrect.

Removing the letters allowed the doodle to be interpreted correctly as showing the transcription of RNA from DNA, which is not only biologically relevant, it’s also a critical component of Khorana’s work. In fact, part of Khorana’s approach involved assiduously avoiding the now-classic behavior of some RNA sequences that might have been unintentionally represented in the original doodle—a strand folding back on itself, base-pairing to form obstinate structures that can actually prevent the reading and translation of the code by cellular enzymes. In addition, synthesizing custom-coded RNA strands was much more difficult than synthesizing DNA strands, so part of the time, Khorana cleverly synthesized DNA strands and allowed the cellular enzymes to make the RNA strands for him.

You can explore how to decode the genetic code yourself using our DNA/RNA simulator!* How would you determine the number of bases (letters) in each DNA word? You can design DNA and RNA sequences that clearly answer this question, and then move on to figuring out how to use your own sequences to reveal the code.

Transcription

The process of transcription. Note that only the red RNA strand includes “U” for Uracil, so the original Doodle’s labels didn’t make sense.

Translation

The process of translation. Here, the top base pairs are passed in by tRNA, and don’t form a strand at all, so this doesn’t match the original Doodle either.

* This Next-Generation Molecular Workbench model was developed thanks to a generous grant from Google.org.

Virtual CRISPR-like techniques engage students in editing dragon DNA

The CRISPR gene editing technique is faster, cheaper, and more accurate than past methods of editing DNA. And it’s creating a huge buzz in the world of science and medical research. By precisely removing, adding, or altering part of the genome, CRISPR enables geneticists to target and edit genes that are associated with genetic diseases—without affecting other areas of the genome, a major drawback of previous approaches.

A recent story (CRISPR, 5 ways) includes a video, produced by Wired magazine, in which a biology professor at NYU explains CRISPR to a seven-year-old, a high school student, a college student, a graduate student, and an expert scientist in the field of genetics. The conversations range from genomes to the value of basic research.

In the final conversation with the expert scientist, the focus shifts to the level of DNA and genome engineering. Scientists who use CRISPR must understand the underlying mechanisms by which the genes affect particular genetic traits and disorders. They’re able to learn about the composition and functionality of genes from model species they study and apply what they’ve learned to another target species (e.g., the mouse is a model species for human genetic disease).

We’ve created an online learning environment that allows middle and high school students to do the same.

Geniventure, dragon genetics software

Geniventure, the next generation of our popular dragon genetics software Geniverse, places students in a virtual underground lab where they perform genetic experiments with drakes, the model organism for dragons. There is real biology behind the mythical drake and dragon genes and traits, which have been carefully compiled from the actual genes and associated traits of the anole lizard, mouse, fruit fly, zebrafish, and other model species used to study genetics. The genes that affect horns, wings, color, and other drake traits are genes that are involved in the development and functioning of similar traits in real organisms.

In our Geniventure game, students zoom into a drake’s genes, see the actual DNA code behind them, and manipulate the resulting proteins as the proteins do the work of producing traits. The first set of protein-based challenges using this new interface revolves around scale color (modeled after the same genes for human skin color) and allows students to edit the genes of an albino drake. After working with the proteins that produce melanin and discovering a broken enzyme that results in an albino drake, students enter the nucleus of the cell to change the drake’s genes (and DNA) from producing the broken enzyme so that it can create the functional protein, ultimately generating a drake with color distributed throughout its scales.

From albino to charcoal (right). In the protein-level challenges, students can view the starting state of their drake’s scale color (Albino), the current state (Lava), and the target state (Charcoal). The Start and Target views also display the distribution of color throughout the drake’s scale cells.

Proteins in action. In the Geniventure Zoom Room, students experiment with proteins and discover how they influence the color of the drake. Students are tasked with manipulating the proteins of an albino drake to restore color to its scales.


Inside the nucleus. In some challenges, students are unable to work with the proteins directly. Instead, they must enter the nucleus where they can alter the drake’s alleles to create the proteins needed to reach the target color.

Making this protein-based link from DNA to trait is critical for students’ ability to make sense of patterns between genes and traits— for example, dominant vs. recessive versions of genes— and to apply the same logic to other genetic phenomena. Through Geniventure, students are able to transfer their experience of editing genes and working with proteins in drakes to an understanding of how scientists are using CRISPR and other techniques.

Our goal is to help students better understand modern science, including biotechnology advances such as CRISPR, to make science engaging and relevant, so students can ultimately envision themselves as future scientists.