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Are there any new proteins?

  1. Jun 6, 2017 #1
    Are there any proteins in any animals that are known to have completed their evolution in the last 1000 years? That is, are there any proteins that exist today that did NOT exist a millenia ago?

    If yes, are the mutation paths known for their origins?
     
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  3. Jun 6, 2017 #2

    Ygggdrasil

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    1000 years ago is very short on an evolutionary timescale, so any new proteins that would have arisen during that timeframe would be confined to a relatively small population. Researchers have studied traits that have evolved within the past ~10,000 years (https://www.nature.com/scitable/topicpage/evolutionary-adaptation-in-the-human-lineage-12397), but I think all of them come about by altering the function of existing proteins and don't create any new proteins.

    I'd search around for work people have done on gene duplication as that is probably one of the most common ways in which new proteins are created. Joe Thornton (now at the University of Chicago) has done some beautiful work tracing the set of mutations that allowed a duplication of the steroid receptor to evolve specificity for binding a new steroid molecule (see for example, http://science.sciencemag.org/content/317/5844/1544)
     
  4. Jun 6, 2017 #3
    There will have been variations of proteins over just 1000 years but for highly evolved life like humans that is too short a time to know if it makes much difference,
    Most variation of a protein is neither useful or harmful.
     
  5. Jun 7, 2017 #4

    BillTre

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    I unusual thoughts on this:

    It depends on what you mean when you ask:
    1) Depends on what you consider evolution. I consider human made creations as evolution, just rather new and not from traditional natural selection. The evolution of dogs and horses are two less weird examples, but there are also lots of new human made proteins in research animals. Modified GFP in flies fish worms mice etc. are more extreme examples, but there are many more. Growth hormones in fish possibly in fish farms. Gene drives etc in insects vectors in attempts to control them (these could soon be released into the wild and subjected to natural selection. To me these are examples of evolution in a larger vista.
    I know some evolutionary biologists who do not think this counts, but I consider lab animals as occupying new niches (in research labs) that have recently opened up.

    2) There are several mutations which are formed from break point mutants sticking parts of two different proteins together to make something new with a new function. I believe, some cancer genes are like this. Some cancer genes may arise in a single individual and be limited to a single individual. Others could have been created generations ago and are inherited.
    Not sure if you would count them as new proteins.

    3) Not sure what exactly completed their evolution means. Many proteins will continue to evolve at some rate.
    In addition, not sure how you would think of natural sequence variation in proteins across a population within this kind of discussion.
    For example, mutations of hemoglobin, which can make humans better adapted to different environments. Among a large population they might arise and revert over and over. Selection on the gene could change as individuals move from one location to another. Is hemoglobin's evolution done?
     
  6. Jun 17, 2017 #5

    1oldman2

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  7. Jun 17, 2017 #6
    But that's not what I'm asking about. I'm wondering about just the proteins observed in use in animals today. They were presumably built up with one amino acid added per mutation over a long long period. But there must have been some point in time when the very last component was added and then it existed as we see it today. So I'm wondering about the last mutation.

    Diseases are easy. Almost any mutation is a disease. So I'm not interested in that.

    Whether it's done or not is irrelevant. It's in use and extremely valuable as it is. And surely it's been valuable for a long time. So the last component must have been added to it to make it useful much more than a thousand years ago.
     
  8. Jun 18, 2017 #7

    BillTre

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    The mutations that have resulted in the genomes (and therefore the genes) of today's creatures are the result of:

    1) point mutations. These affect only a single base pair of genetic sequence.
    Point mutants and even sequence changes affecting only small regions are among the simplest changes to the genome sequence.

    2) Break point mutations are the result of breaks in the chromosome and the resulting changes in the sequence. These are the result of a break in the DNA molecule that is making up a chromosome. These kinds of mutation can affect large areas depending the number of breaks on how DNA repair mechanisms owrk things out, like arms of chromosomes or only relatively small regions (like deleting a few base pairs), Simple results could be the removal, inversion (flip end-to-end), removal to a different location, duplications of regions, things like that. These kinds of changes can also affect individual genes (kind of small to intermediate sequence size) and can result in switching in and out whole sections of sequence and result in more complex genetic changes. This can take a part of one gene and stick it onto or switch it in or out of a gene's sequence. This can result in large and interesting changes in a gene's sequence or duplicating whole genes or gene regions. Duplicated genes can then be changed independently by point mutations so that one gene maintains the ancestral function while a second copy can be evolved to a new function.

    Because these kinds of changes affect lots of genetic parts, they can have big effects on function. However, big changes are less likely to produce something that can survive (most would be lethal mutations).

    3) There are also gene changes of genetic origin. These could include genome changes due to genetic transposons, retroviruses, and other things that move around or make duplications in the genome over generations of time. They produce similar genetic results to breakpoint mutations in that they move around chunks of sequence (either their own or some they might have picked up from their current or a former host). They can make thousands of copies of themselves in the genome, some of which might affect protein evolution.

    Evolution sorts through thousands or millions of all these kinds of mutations to come up with a few useful changes that are adaptive.
    These kinds of changes can account for a lot of current gene diversity.

    There are at least most of the kinds of mutations that would be involved in generation current protein sequence. Which ever came last would be what you want I guess. I would also guess that those would be most likely to be point mutants, but probably not always.

    Hemoglobin is under different selection pressures depending on the environment it is found in. If a reproductive unit moves from an environment favoring one functional trait to another favoring a different traits (which can happen sometimes when people move) then the gene will experience new selective pressures and its sequence should change over a time of generations.
    The evolution of a gene is frequently thought of as how the population of the genes sequences in the breeding population of the species changes over time. This will be on a generation time scale with a lot of sequence variants co-existing in a population.
     
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