A genome study has discovered a gene which explains the beak variations that led Charles Darwin to develop his theory of evolution.
Darwin started to think that species could evolve as they adapt to new environments after observing the variations in the shape and size of the beak of finches on the Galapagos Islands. An explanation for this variation could have been discovered after scientists from Uppsala University in Sweden sequenced the genome of 120 birds of 15 different species of Darwin’s finch, writes Rhodi Lee of Tech Times.
Finch beak variations
The study was published in Nature on February 11, and the study was led by Leif Andersson. The team compared the pointed-beak Darwin’s finch with the blunt-beak species, and discovered that a gene known as ALX1 was linked to the beak variations between those two species, as well as variations in the medium ground finch species. The medium ground finish is well-known for the fast changes their beaks exhibit during times of drought.
“The most thrilling and significant finding was that genetic variation in the ALX1 gene is associated with variation in beak shape not only between species of Darwin’s finches but also among individuals of one of them, the medium ground finch,” Andersson said.
The ALX1 gene is crucial in the formation of head and facial bones. Human deformities such as cleft palate are caused by the malfunctioning of this gene, but different beak sizes are Darwin’s finches are caused by slight differences in ALX1.
Hybridization in Darwin’s finches
According to the research, those finches with the bluntest bills had inherited the “blunt” ALX1 from both parents, mixed inheritance led to intermediate beaks, while two “sharp” ALX1 genes led to offspring with the pointiest beaks.
The variety of shapes and sizes of beaks would suggest that genes have transferred between species as a result of interbreeding. According to the researchers they have been able to prove that hybridization has been occurring over the entire course of their evolution.
“We have previously shown that beak shape in the medium ground finch has undergone a rapid evolution in response to environmental changes,” said researcher Rosemary Grant of Princeton University.” Now we know that hybridization mixes the different variants of an important gene, ALX1.”