Question Video: Recalling Mendel’s Law of Segregation | Nagwa Question Video: Recalling Mendel’s Law of Segregation | Nagwa

Question Video: Recalling Mendel’s Law of Segregation Science • Third Year of Preparatory School

Join Nagwa Classes

Attend live Science sessions on Nagwa Classes to learn more about this topic from an expert teacher!

Following on from Mendel’s work, some laws of inheritance were written. Which law of inheritance describes how factors that produce certain traits are separated from each other when gametes (sex cells) are formed?

02:43

Video Transcript

Following on from Mendel’s work, some laws of inheritance were written. Which law of inheritance describes how factors that produce certain traits are separated from each other when gametes, sex cells, are formed? (A) The law of segregation, (B) the law of independent assortment, (C) the law of dominance.

Gregor Mendel conducted research on hereditary and pea plants and used his work to postulate three laws. The first law is the law of independent assortment. This states that genes segregate independently during gamete, or sex cell, formation. A gene is a sequence of DNA that contains the information needed to produce a certain characteristic, for example, flower color. So, when an offspring inherits the characteristic of flower color, this is independent of inheriting another characteristic, like seed color. These two characteristics aren’t linked.

The second law is the law of dominance. Here, one trait can conceal another trait for the same characteristic. So, with the characteristic of flower color, we can have a plant with two flower color traits, like yellow and pink. This is caused by two different versions of the flower color gene. And suppose if we breed these plants, we only see yellow flower plants as offspring. The gene version for the yellow flower trait in this case is said to be dominant to the gene version for the pink flower trait because it conceals its expression.

The third law is the law of segregation. This states that an organism has two copies of a gene that are separated when gametes form. This gene can exist as different versions to make different traits for a characteristic. So, let’s say we have the characteristic of seed color and two traits, yellow and green seed color. We’ll represent the yellow seed color version as an uppercase Y and the green seed color version as a lowercase y.

The organism has two copies of this gene, one is the uppercase Y and the other is lowercase y. When gametes are produced, each gamete will receive one copy. So here, we have two gametes being formed, each with one copy of the gene, either the yellow seed color version or the green seed color version. So, these different versions of the gene that produce different traits are separated when gametes are formed.

Therefore, the correct answer is (A), the law of segregation.

Join Nagwa Classes

Attend live sessions on Nagwa Classes to boost your learning with guidance and advice from an expert teacher!

  • Interactive Sessions
  • Chat & Messaging
  • Realistic Exam Questions

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy