• Question: What does the human genome look like and how's it changed since prokayotes?

    Asked by daniel2xmas18 to Anthony on 9 Jan 2019.
    • Photo: Anthony Redmond

      Anthony Redmond answered on 9 Jan 2019:

      It’s a little hard to explain with words only what a genome looks like. But here are some useful links that might help:



      A LOT of changes have occurred between humans (and most other eukaryotes) and our prokaryotic ancestors. Among the most obvious of these that the genomes of prokaryotes don’t have paired chromosomes like we do and are not contained within a nucleus like ours. Prokaryote genes don’t have introns (gaps within the gene that contain sequence that does not code for proteins), which allow for eukaryotes such as ourselves to produce different variants of proteins from a single gene. Prokaryote genomes are also usually far far smaller than ours, as eukaryotic genomes typically possess large amounts of structural, regulatory, and parasitic DNA. Prokaryotes can have smaller pieces of DNA within their cells called plasmids that often carry antibiotic resistance genes, and can be transferred between species, whereas eukaryotes often have additional genomes within organelles, such as chloroplasts or mitochondria (which were once ancient bacteria).


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