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Phenotype plasticity

Identical twin astronauts, Mark Kelly and Scott Kelly, help illustrate differences between genotype (genetic info) and phenotype (observable traits). Despite their identical genotypes, environmental factors like the time Scott spent in space led to differences in the phenotypes of the twins, showcasing the concept of phenotype plasticity. Created by Sal Khan.

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  • blobby green style avatar for user Brielle Alder
    What is the difference between phenotype and exegenetics?
    (6 votes)
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    • leaf red style avatar for user B L Ø Ø ᑐ | Я ᕮ ᑐ | Γ Λ L L
      Well, first of all, it's epigenetics, not exegenetics.
      Secondly, these two are not in the same category. the word phenotype represents the specific expression of the genotype, while epigenetics refers to the subject of studying how your behaviors and environment can cause changes that affect the way your genes work. One refers to a term specific to the study of genetics, the other refers to a type of genetic studying.
      Thirdly, Phenotype refers specifically to the physical and behavioral characteristics of an organism, while epigenetics is focused on changes in gene function that occur without a change in the underlying DNA sequence.
      Fourth, Phenotype is determined by both genetic and environmental factors, while epigenetics is primarily influenced by environmental exposures and developmental experiences.
      Last, Epigenetic changes can affect how genes are expressed, leading to differences in cellular behavior and development, while the phenotype is the observable expression of an organism's genetic makeup.

      Hope that helps :]
      (1 vote)
  • duskpin ultimate style avatar for user RiverclanWarrior
    What are some examples of inherited diseases? Just out of curiosity...
    (3 votes)
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    • male robot donald style avatar for user Tybalt
      This is no means a complete list, but some inherited diseases include:
      -Sickle Cell Anemia (red blood cells are shaped like sickles, making them die early and restrict the flow of blood)
      -Huntington Disease (causes destruction of nerve tissue)
      -Marfan Syndrome (affects connective tissue)
      -Tay-Sachs Disease (destroys nerves in the brain and spinal cord)
      (4 votes)
  • blobby green style avatar for user lydmic123
    What's the difference between phenotypic plasticity and acclimatization?

    (2 votes)
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    • starky sapling style avatar for user 24ebeck
      The ability of a single genotype to generate a variety of phenotypes in response to environmental changes is termed phenotypic plasticity and the resulting increase of tolerance to stressful levels of environmental parameters is known as acclimation.
      (4 votes)
  • duskpin ultimate style avatar for user moonchicken123
    Are genes and the environment the only things that affect the phenotype?
    (2 votes)
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    • piceratops ultimate style avatar for user RowanH
      I think so, because you could count anything that is not the genes as 'the environment', even if it is something in the environment that you were exposed to a long time ago.
      Having said that, gene expression is affected by epigenetics, for example how the DNA is methylated. Epigenetics is affected by the environment. There is some debate as to whether epigenetic modifications can be passed on from one generation to the next. If they are, then phenotype could be affected by environmental factors that you personally did not encounter, but maybe your parents did.
      (2 votes)

Video transcript

- [Instructor] The folks you see in this picture are two NASA astronauts who also happen to be identical twins. On the left here, this is Mark Kelly, you can see his name on his patch right over there, and then this is Scott Kelly. And the reason why we want to look at these two astronauts in particular is to think about genotype and phenotype that we have been introduced to in other videos. So just as a bit of a review, when people talk about genotype, they're talking about the actual genetic information encoded in an organism's genes. So, if you go inside a cell we have chromosomes and then on those chromosomes, there are long, each chromosome's a long stretch of DNA. And then sections of that long stretch of DNA will code for various things, often usually various proteins. But there's a difference between what is actually, what information is in one's genes versus what actually gets expressed. The observable characteristics, that is phenotype, and two people with the same genotype they might have a very similar phenotype but they won't necessarily have an identical phenotype because above and beyond the genes affecting phenotype, you also have the environment affecting someone's phenotype. So, as you can see here, Mark and Scott Kelly, they're identical twins, they have the same genotype. But if you just look at their facial characteristics you can see that you could tell the difference between the two, and it's not just the fact that Mark has a mustache and that Scott doesn't, we could draw in a mustache, we would still see that they look different. And that's because their bodies developed in different ways based off the environment that they happen to be in. And this idea that the same genotype could result in variations of phenotype, this is known as phenotype plasticity. Phenotype. Phenotype plasticity. And maybe in one of the most extreme experiments ever conducted on phenotype plasticity, NASA was intrigued to see, well, what would happen to the gene expression if Scott Kelly spent an extensive period of time in space while his twin brother didn't. So they looked at how their bodies expressed certain characteristics before Scott spent an extended period of time in space. And then after he spent that time in space they studied his body and they saw that there was differences in the mitochondria, differences in which genes were expressed. In fact, there was a 7% difference in the gene expression after the extended time in space for Scott. So that's the example of that space environment changing Scott's phenotype. And the NASA scientists theorized that it was a low oxygen environment there was a lot of carbon dioxide in that environment, there were stressors from space travel that would have affected how the genotype which is identical to his brother, Mark's genotype, how it might have been expressed resulting in the phenotype plasticity above and beyond what other changes in phenotype between Scott and Mark accumulated over the course of their lives despite having the same genetic information.