Low genetic variation or a lack of genetic diversity increases the risks of extinction. Scientists have observed this in cheetah populations. Captive feline cheetahs at a breeding colony for large cats were exposed to a viral pathogen that killed roughly 50% of the cheetah population. None of the lions in the large cat population developed symptoms or were affected. Scientists know that lions have a more extensive genetic variation, which means they had the gene variations in their immune system necessary to fend off the disease. Describe the evidence that supports how the cheetah population is likely experiencing a lack of genetic diversity. Suggest one way humans can intervene to increase genetic diversity. Predict a potential adaption that could result from this increase in diversity.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.