Evolutionists used to dismiss them us junk, as useless leftovers from the assumed millions of years of blind Darwinian processes.
Roughly ten per cent of our genome consists of Alu sequences or small repetitive elements known as jumping genes. According to an EurekAlert! article:
“They were considered for a long time as ‘junk’ DNA, because, although they are transcribed into RNA, they encode no proteins and do not seem to participate actively in the cell's functions.”
Now, however, Professor Katharina Strub, at the Faculty of Science of the University of Geneva, and her colleagues discovered that Alu sequences “regulate the activity of ribosomes and contribute to the cell's immunity.”
The article explains how jumping genes do it:
“Alu RNA can bind to specific proteins forming a complex called Alu RNP … this complex allows the cells to adapt to stress caused for example by chemical poisoning or viral infection … the same complex plays a role in protein synthesis by regulating the number of active ribosomes, suggesting that it could be part of the innate system of cellular defense against certain viruses.”
The most logical explanation for why our genome looks designed is that it is designed. While Darwinian mechanisms cannot explain its existence, the work of the All-Power and All-Wise Creator certainly can.
Jumping genes have essential biological functions. EurekAlert! 19 February 2015.