Phenotype plasticity | Heredity | AP Biology | Khan Academy
Summary
TLDRThe video script discusses the concept of genotype and phenotype through the example of NASA astronauts and identical twins, Mark and Scott Kelly. It explains that despite sharing the same genetic information (genotype), observable characteristics (phenotype) can vary due to environmental influences, a phenomenon known as phenotype plasticity. The script highlights a study where Scott's year-long stay in space resulted in a 7% gene expression difference, illustrating the impact of the space environment on his phenotype, which differed from his twin brother's.
Takeaways
- 🌌 The script discusses two NASA astronauts, Mark and Scott Kelly, who are identical twins.
- 🧬 Genotype refers to the genetic information encoded in an organism's genes, which includes DNA sequences on chromosomes.
- 👤 Phenotype is the observable characteristics of an organism, which can vary even among individuals with the same genotype.
- 🌿 The environment plays a significant role in affecting an individual's phenotype, beyond the influence of their genes.
- 👬 Identical twins Mark and Scott Kelly have the same genotype, but their phenotypes are not identical due to environmental factors.
- 🚀 NASA conducted an experiment to study the effects of space travel on gene expression, focusing on Scott Kelly's extended stay in space.
- 🔍 Before and after Scott's space mission, scientists compared his body's expression of certain characteristics to his twin brother's.
- 🌌 Differences in mitochondria and gene expression were observed in Scott after his time in space, highlighting the impact of the space environment.
- 🔢 A significant 7% difference in gene expression was noted in Scott compared to his twin, demonstrating the extent of phenotype plasticity.
- 🌐 The space environment, characterized by low oxygen and high carbon dioxide levels, was theorized to have influenced Scott's gene expression and phenotype.
- 🧪 The study of the Kelly twins provides insights into how identical genotypes can result in different phenotypes due to environmental influences.
Q & A
Who are the two individuals in the picture mentioned in the script?
-The two individuals in the picture are Mark Kelly and Scott Kelly, both NASA astronauts and identical twins.
What is the main focus of the script regarding Mark and Scott Kelly?
-The script focuses on the concepts of genotype and phenotype, using Mark and Scott Kelly as examples to illustrate how environmental factors can influence phenotype despite identical genotypes.
What does the term 'genotype' refer to in the context of the script?
-Genotype refers to the actual genetic information encoded in an organism's genes, which includes the DNA sequences on chromosomes that code for various proteins and characteristics.
What is meant by 'phenotype' as discussed in the script?
-Phenotype refers to the observable characteristics of an organism, which can be influenced by both genetic information (genotype) and environmental factors.
Why might two people with the same genotype not have identical phenotypes?
-Two people with the same genotype might not have identical phenotypes because environmental factors can influence how genes are expressed, leading to variations in phenotype.
What is the concept of 'phenotype plasticity' explained in the script?
-Phenotype plasticity is the idea that the same genotype can result in variations of phenotype due to different environmental influences on gene expression.
What experiment did NASA conduct involving Scott Kelly to study phenotype plasticity?
-NASA conducted an experiment where Scott Kelly spent an extended period in space while his twin brother, Mark, did not, to observe the effects of the space environment on gene expression and phenotype.
What were some of the differences found in Scott Kelly's body after his extended stay in space?
-After Scott Kelly's extended stay in space, differences were found in his mitochondria and in the expression of certain genes, with a 7% difference in gene expression compared to before his space mission.
What environmental factors in space might have contributed to the changes in Scott Kelly's phenotype?
-The environmental factors in space that might have contributed to the changes in Scott Kelly's phenotype include a low oxygen environment, high levels of carbon dioxide, and stressors associated with space travel.
How did the space environment affect the expression of Scott Kelly's genes, according to the script?
-The space environment affected the expression of Scott Kelly's genes by causing changes in mitochondria and gene expression, resulting in a 7% difference in gene expression and demonstrating phenotype plasticity.
What does the comparison between Mark and Scott Kelly demonstrate about the influence of environment on phenotype?
-The comparison between Mark and Scott Kelly demonstrates that even with the same genetic information (identical genotype), environmental factors can lead to differences in how genes are expressed, affecting the observable characteristics (phenotype) of an individual.
Outlines
🚀 Phenotype Plasticity in Identical Twins
The video introduces NASA astronauts Mark and Scott Kelly, identical twins, to explore the concepts of genotype and phenotype. Genotype refers to the genetic information encoded in an organism's DNA, while phenotype is the observable characteristics expressed by an organism. The video highlights that even with the same genotype, environmental factors can lead to variations in phenotype, a concept known as phenotype plasticity. The Kelly twins serve as an example of this, with Scott's extended stay in space resulting in a 7% difference in gene expression compared to his brother, illustrating the impact of the space environment on phenotype.
Mindmap
Keywords
💡Genotype
💡Phenotype
💡Identical Twins
💡Chromosomes
💡DNA
💡Proteins
💡Phenotype Plasticity
💡Gene Expression
💡Mitochondria
💡Space Environment
💡NASA
Highlights
Introduction of identical twin NASA astronauts, Mark and Scott Kelly.
Discussion on genotype and phenotype and their differences.
Explanation of genotype as the genetic information encoded in an organism's genes.
Description of chromosomes and DNA as carriers of genetic information.
Differentiation between genotype and phenotype in terms of observable characteristics.
The influence of environment on phenotype, even among individuals with the same genotype.
Observation that identical twins Mark and Scott Kelly have different facial characteristics.
Introduction of the concept of phenotype plasticity.
The idea that phenotype plasticity can result from the same genotype.
NASA's experiment on phenotype plasticity by comparing Scott Kelly's gene expression in space.
Pre-space mission comparison of gene expression in Scott and Mark Kelly.
Post-space mission differences in Scott Kelly's gene expression.
A 7% difference in gene expression observed in Scott Kelly after extended time in space.
The impact of the space environment on Scott Kelly's phenotype.
Theoretical contributions on how low oxygen and high carbon dioxide levels in space affect gene expression.
The role of stressors from space travel in altering gene expression.
The potential implications of these findings on understanding the interaction between genotype and environment.
Transcripts
- [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.
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