The full-length (i. e., containing the entire protein-coding region) cdna for a specific eukaryotic gene in humans is 1500 nucleotides long. you screen a pig genomic library with this cdna and isolate two genomic clones of different lengths. both clones are sequenced and found to be 1900 and 2100 nucleotides long from start codon to stop codon. screening of genomic libraries of several other organisms reveals that all of them contain only one genomic clone -- pigs seem to be the exception to the rule here. what evolutionary events might have led to the presence of two genomic clones in pigs, and the discrepancies in their length compared to the cdna probe? how is this representative of a general type of occurrence in molecular genetic evolution?

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.

what are the awnser choices? i mean, without choices, it is an incompleat

want or the answer