Dinosaurs from the Lab - the origin of the beak and palate, Pure Science
The year 1993 was the year marked by the Steven Spielberg's movie - Jurassic Park.
I was 7 back then and who knows, maybe it traced my future interests in molecular biology.
I prepared something seriously scientific for today:
Bhullar, Bhart‐Anjan S., et al. "A molecular mechanism for the origin of a key evolutionary innovation, the bird beak and palate, revealed by an integrative approach to major transitions in vertebrate history." Evolution 69.7 (2015): 1665-1677.
The paper is available here
The importance of the beak
From the ecological point of view, beak is an incredible tool that allowed the access to all sorts of food.
It also means that it's very important for the evolution as well, as the selection can be efficiently applied to this particular organ. Today, there are more than 10.000 different species of birds, making them one of the most successful vertebrates.
Genes behind the formation of beak
A common misconception in general public is that we don't know how the organs evolved. It's simply not true.
In case of all the organs, it's known to the level of the genes.
Beak is under control of the Fibroblast growth factor 8 (Fgf8) and Sonic hedgehog (Shh) genes.
Comparison of various organisms
The common logic in comparative analysis is to take the members of the same group (birds), mix them together with the relatively close group (dinosaurs) and add some outliers (mammalians).
The plot you see is the PCA plot (principal component analysis), a statistical method for the reduction of dimensionality.
For example, you measure 10 parameters in 1000 samples. After the application of PCA, you get the principal components which are new parameters that explain the most of the difference among the samples.
For example, if you take a cloud of dots on the straight line in XY coordinate system, you can explain their position with 2 values X and Y. But you can also rotate the axes and explain the vast majority of the variance among the data with the values along new axis X2. Y2 values are negligible.
In conclusion, yes, the beak of the birds is closely related to the analogue structures in dinosaurs.
Molecular genetics in action
With the selective switching of the genes mentioned before within the chicken embryos, it was possible to obtain the ancient structures.
So the structures are marked as blue.
When we selectively switch the genes (there are only two genes) those structures can be changed in the way that become ancestral (like in dinosaurs, gray area).
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