Genetic Concepts and Interactions

Dr. Kali Rasi discusses intragenic interactions, focusing on co-dominance, lethal genes, and pleiotropy. Co-dominance is explained with examples from plants and animals, highlighting the simultaneous expression of alleles. Lethal genes, first observed in snapdragons, are described as recessive alleles causing organism death. Pleiotropy is introduced as a single gene affecting multiple traits, with examples from garden peas and sickle cell anemia.

What are intragenic interactions?

• Interactions between different genes

• Interactions between alleles of a gene

• Interactions between cells

• Interactions between proteins

In co-dominance, how are the alleles expressed?

• Neither allele is expressed

• Alleles blend together

• Both alleles are expressed simultaneously

• Only one allele is expressed

Which of the following is an example of co-dominance in humans?

• ABO blood group

• Skin color

• Eye color

• Height

What technique is used to study co-dominance in plants?

• Microscopy

• Gene sequencing

• Electrophoresis

• PCR

What is a lethal gene?

• A gene that is always dominant

• A gene that enhances survival

• A gene that causes death

• A gene that causes mutations

In snapdragon plants, what type of lethality is observed?

• Co-dominant lethality

• Dominant lethality

• Incomplete lethality

• Recessive lethality

What is the genetic ratio observed in the F2 generation of snapdragon plants with lethal genes?

• 2:1

• 3:1

• 1:2:1

• 1:1

What is pleiotropy?

• Genes that do not affect any traits

• Multiple genes affecting a single trait

• Genes that only affect one trait

• A single gene affecting multiple traits

Which of the following is an example of pleiotropy in humans?

• Blood type

• Sickle cell anemia

• Eye color

• Hair texture

In garden peas, which traits are controlled by a single gene due to pleiotropy?

• Flower size, seed shape, and stem thickness

• Root color, leaf texture, and flower scent

• Height, leaf size, and root length

• Flower color, seed color, and leaf spot