Trying to get a better understanding of the process of DNA to proteins.

So when we have a gene, it is read from the 5' to 3' end, only translating the exons to mRNAs. A single gene can have multiple exons, and use alternative splicing to create different transcripts. A transcript may result in mRNA (not necessarily right? Also other kinds of RNA?) which is translated to amino acids. Finally folded to a functional protein.

My question here, are there different transcripts (say in different genes) that encode for the same protein?

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    $\begingroup$ Yes, they arise because of gene duplication but usually the protein is not exactly similar but quite similar. These genes are called paralogs. $\endgroup$ – WYSIWYG Aug 7 '15 at 8:48
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    $\begingroup$ yes, for example, if one gene came from you mother and another from your father, they might be different enough to cause disease (see sickle-cell anemia or cystic fibrosis). $\endgroup$ – aaaaa says reinstate Monica Aug 7 '15 at 8:51
  • $\begingroup$ As I understood it, a transcription is a combination of exons being used for, for instance, creation of proteins. I'm not referring to point mutations and such, because than another protein will be made by the transcript. Most probably not a protein which is created in another gene. $\endgroup$ – Danielson Aug 7 '15 at 8:57
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    $\begingroup$ Just a point of clarification: you say "it is read from the 5' to 3' end, only reading the exons" but this is not the case. The cell's transcription machinery reads the entire gene until it comes to a "stop" sequence. The resulting pre-mRNA is then spliced to produce the actual mRNA(s) that are translated into proteins. It is during this splicing that introns are cleaved out. $\endgroup$ – MattDMo Aug 7 '15 at 13:49
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    $\begingroup$ Yes there are, and a great example is microtubule-associated protein tau, the key protein component of the paired helical filament of Alzheimer's disease. In this case differential mRNA splicing gives rise to four different protein forms (isoforms) of bovine tau and six different isoforms of human tau, differing in relative molecular mass. The isoforms may be easily distinguished on an SDS-gel. $\endgroup$ – user1136 Aug 7 '15 at 13:59

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