Despite the great diversity of shapes and sizes that exist in nature, a series of general laws common to all of them persist , including humans. These laws are determined by just a few genes called “Hox” in multicellular organisms. Now, a team of scientists from the University of Geneva (Switzerland) has succeeded in discovering that the development of the fingers and genitals is regulated by exactly the same DNA fragment and that the other is derived from one of these structures.
The hox genes are in turn regulated by an adjacent DNA fragment. Once these genes elaborate the “construction plan” of the organism through the axis from head to tail, they begin with the development of the external genitalia and fingers, according to the study published in the journal Science . That is, the same DNA sequence that controls the architect genes is what starts the development of these two structures through very small modifications in the general development process.
“We wanted to determine how this regulation of identical Hox genes is achieved when they are expressed in different contexts “, explains Nicolas Lonfat, co-author of the work. Thus, the formation of the penis, the clitoris and the fingers, depend on minute differences in the use of regulatory DNA sequences.
Which of them came first? “However, it is difficult to determine which came first, as both the fingers and the genitals probably had great adaptive value at the time of the transition from the aquatic to the terrestrial environment,” Lonfat comments.
According to the researchers, this finding could explain why some genetic syndromes in humans are associated with malformations in these structures: such as hypospadias in the penis (the opening of the urethra is not at the end of the penis) or polydactyly (the appearance of fingers additional) or brachydactyly (very short fingers).
