Regulatory Genes and Gene Expression

The video explores the role of the Pax6 gene in eye development across various species, including humans, mice, and fruit flies. It discusses how mutations in Pax6 can lead to eye defects and how overexpression can induce eye tissue in non-eye body parts. The video also covers the concept of master regulatory genes, which control the expression of other genes, and their role in limb development in vertebrates. The Pitx1 gene's role in the evolution of limb structures in sticklebacks is highlighted, showing how genetic regulation can lead to significant morphological changes.

What is the primary role of the Pax6 gene in different organisms?

• To control limb development

• To regulate eye development

• To enhance muscle growth

• To improve digestive functions

What happens when there is a mutation in one copy of the Pax6 gene in humans?

• The entire eye is eliminated

• The iris muscle is lost

• The eye size increases

• The pupil becomes smaller

In fruit flies, what is the result of overexpressing the Pax6 gene during leg development?

• Loss of wings

• Increased body size

• Induction of eye tissue on the leg

• Formation of additional legs

How do master regulatory genes like Pax6 function in gene expression?

• By altering DNA sequences

• By switching other genes on and off

• By increasing cell division

• By directly coding for proteins

What is the role of regulatory switches in gene expression?

• They code for proteins

• They determine where and when genes turn on

• They increase the number of chromosomes

• They delete unnecessary genes

Which gene is expressed in the wing of a chick but not in the leg?

• tbx5

• tbx4

• pitx1

• Pax6

What is the function of the pitx1 gene in vertebrates?

• It controls eye color

• It enhances brain function

• It determines skin pigmentation

• It regulates hind limb development

In sticklebacks, what genetic change is associated with the loss of hind limbs?

• Mutation in the coding region of pitx1

• Deletion of the pitx1 gene

• Inactivation of a regulatory switch for pitx1

• Duplication of the pitx1 gene

What remains unchanged in the pitx1 gene of sticklebacks despite limb loss?

• The gene's expression in the head

• The gene's location

• The protein coding region

• The regulatory switches

How does evolution utilize regulatory switches to create morphological changes?

• By changing the protein structure

• By increasing the number of genes

• By tweaking the switches to modify gene expression

• By altering the DNA sequence