Why did dna technology lead to the use of cladistics?
In 1950, Willi Hennig developed cladistics as a classification system for organisms that relies on morphologic characteristics rather than genetic information. Hennig argued that a group of organisms sharing similar morphological characteristics should be classified as a single clade. Hennig’s cladistic system is still widely used today. However, the invention of DNA technology allowed scientists to study molecular genetic information and to incorporate it into phylogenetic trees.
With recombinant DNA technology, scientists can isolate a segment of an organism’s gene, study its transcript and nucleotide sequence, mutate the gene in very specific ways and then reinsert it into a living organism. This allows for more accurate phylogenetic analysis because it avoids the errors that may occur in comparing morphologic traits.
Scientists use cladistics to build phylogenetic trees, which show how species evolved from common ancestors. They also analyze the differences between morphologic and molecular data. They then use computer programs to analyze the results and build a cladogram, which is a branching diagram of the hypothesized evolutionary history of the different organisms.
Cladistics has many applications in medicine and agriculture. One of the most notable uses is in forensics, where it helps to solve crimes by using DNA from crime scenes to identify suspects. Scientists look for short tandem repeats in the DNA, also known as STRs. These are short segments of DNA that appear in high amounts and to varying degrees between people and can be used as evidence of identity and relationships.
