g It was noted in the Experimental Pathways feature in Section 10.4 that at least two- thirds of the human genome is derived fro
m transposable elements. The actual number could be much higher, but it is impossible to make a determination about the origin of many other sequences. Why do you suppose it is difficult to make assignments about the origin of many of the sequences in the human genome
TEs are repetitive and mobile elements, thereby it is hard to trace their origins
Explanation:
Repetitive elements are patterns of nucleotide sequences in the DNA characterized to have multiple copies throughout the genome. DNA mini-satellite and Transposable Elements (TEs) are some examples of highly repetitive DNA. TEs are repetitive mobile elements that have the ability to jump within the genome and occupy a major part of eukaryotic genomes. For instance, there is a type of TEs called retrotransposons which mobilize through a copy-and-paste mechanism, thus increasing their number in a genome. In consequence, TEs represent highly repetitive and dynamic genomic sequences, and thereby it is hard to trace their evolutionary histories.
If the enzyme changes shape, the active site may no longer bind to the appropriate substrate and the rate of reaction will decrease. Dramatic changes to the temperature and pH will eventually cause enzymes to denature.
