Molecular Development and The Arthropod Head Problem
The study of how developmental genes are expressed during embryogenesis has become an important new tool in the last twenty years for understanding the structure and evolution of morphology. The arthropod head problem has been tackled in three main ways in this regard, first by using genetic segmental markers to probe the obscure region in front of the mouth, especially in insects; second by looking at Hox gene expression patterns to detect patterns of homology between different arthropods; and third, by studying gene expression in particular features (especially the labrum) to determine its appendiculate or other status. Because all arthropods have the same complement of nine Hox loci, the morphological diversification observed is caused by these genes being expressed at different areas and times.
Read more about this topic: Arthropod Head Problem
Famous quotes containing the words development, head and/or problem:
“I can see ... only one safe rule for the historian: that he should recognize in the development of human destinies the play of the contingent and the unforeseen.”
—H.A.L. (Herbert Albert Laurens)
“It is better to be the head of the chicken than the tail of an ox.”
—Chinese proverb.
“Hypocrisy is the essence of snobbery, but all snobbery is about the problem of belonging.”
—Alexander Theroux (b. 1940)