What is an Allele? Quick Definition

Summary

In this 'Quick Definitions' video, John Perry explains the concept of an allele in genetics. An allele is an alternative version of a gene, which can determine traits like eye color in organisms. For instance, a frog might have a 'yellow allele' for its eye color gene, while another frog could have a 'red allele'. Alleles can arise through mutations and compete within a population. If an allele offers a survival advantage, it can become dominant, leading to the fixation of that trait within the population. The video simplifies complex genetic concepts, making them accessible to viewers.

Takeaways

• 🧬 Genes are stretches of DNA that code for specific proteins or serve as templates for functional RNA chains.
• 👁️ An allele is an alternative version of a gene, such as one that codes for a different eye color in a frog species.
• 🐸 Multiple genes and environmental factors often interact to determine an organism's traits, like eye color.
• 🧬 Most animals have two copies of their DNA, meaning they can have two different alleles for a gene.
• 🌱 Most alleles do not affect an organism's observable traits.
• 🔄 New alleles are created through mutations, which can introduce variations into a population's gene pool.
• 🦎 If a new allele provides a survival advantage, it may become more common over generations, potentially leading to the fixation of that allele in the population.
• 🏆 When an allele becomes dominant in a population, it can lead to the extinction of other alleles.
• 👕 The video is from the 'Stated Clearly' series, which provides clear explanations of scientific concepts.

Q & A

What is a gene in genetics?

A gene is a stretch of DNA that codes for something, either specific proteins or functional chains of RNA, which in turn produce traits in organisms.

How do genes relate to an organism's traits?

Genes code for proteins and RNA chains that produce traits, such as eye color and bone length, so genes indirectly code for an organism's traits.

What is an allele?

An allele is an alternative version of a specific gene, which can result in different expressions of a trait, like different eye colors in the example of the frog.

Why are alleles important in genetics?

Alleles are important because they provide variation within a species, which can lead to different traits and potentially influence survival and reproduction.

How do new alleles come into existence?

New alleles come into existence via mutations, which are changes in the DNA sequence that can create new versions of genes.

Can an organism have more than one allele for a gene?

Yes, most animals have two copies of their DNA, meaning a single animal can have two different alleles for any given gene in its genome.

What is the term for when an allele becomes dominant in a population?

When an allele dominates an entire population, replacing other versions, this is called fixation.

How can an allele provide a survival advantage?

An allele might provide a survival advantage if it helps an organism better adapt to its environment, such as blending in to avoid predators.

What happens to an allele that does not provide a survival advantage?

Alleles that do not provide a survival advantage may be outcompeted by other alleles and could eventually become extinct within a population.

Are all alleles observable in an organism's traits?

No, most alleles do not have any observable effect on an organism's traits, and their influence may be subtle or require specific environmental conditions to manifest.

How does the presence of multiple genes and environmental factors affect an organism's traits?

Multiple genes and environmental factors can interact in complex ways to determine an organism's traits, making the relationship between genes and traits not always straightforward.