Are identical twins exactly alike??? Flashcards
Sc (14 cards)
What type of twins come from 1 egg and 1 sperm?
Monozygotic (Identical Twins)
Monozygotic twins always share 100% of their DNA.
How many embryos are formed from one egg in monozygotic twins?
2 embryos
What is a defining characteristic of the sex of monozygotic twins?
Always the same sex
What is the genetic sharing percentage between dizygotic twins?
About 50%
What type of twins come from 2 eggs and 2 sperm?
Dizygotic (Fraternal Twins)
Dizygotic twins can be the same or different sex.
How do dizygotic twins compare to regular siblings?
Like regular siblings born at the same time
What are two factors that can cause identical twins to not be exactly alike?
- Nutrients from the placenta before birth
- Different life experiences after birth
What is the epigenome?
A set of chemical tags that control gene activity (on/off)
The epigenome can be affected by age, diet, stress, and pollution.
What can cause changes in the epigenome over time?
Age, diet, stress, pollution
When do mutations typically occur in twins?
Early in development as cells divide
What can tiny DNA changes in twins affect?
- Personality
- Health
- Physical traits
True or False: Twins raised together always have the same life experiences.
False
Fill in the blank: Identical twins share _______ of their DNA.
100%
Fill in the blank: Dizygotic twins usually don’t look exactly _______.
alike
