General gene editing concepts

Question 1

Chimera

Answer 1

This thing is called a chimera from the Greek monster with parts from
different animals.

Question 2

Embryonic stem cell

Answer 2

Embryonic stem cells (ESCs) are pluripotent stem cells that are derived from the inner cell mass of a developing embryo. They have the ability to differentiate into any cell type in the body, which makes them a valuable tool for research and regenerative medicine.

ESCs are typically obtained from fertilized eggs that have been donated for research purposes, often from in vitro fertilization (IVF) clinics. The inner cell mass is isolated from the blastocyst stage of the embryo and cultured under specific conditions that allow the cells to remain in an undifferentiated state. These conditions involve the use of specific growth factors and a feeder cell layer to provide a supportive environment for the ESCs.

Once the ESCs have been cultured and expanded, they can be induced to differentiate into various cell types, such as neurons, muscle cells, and blood cells, among others. This differentiation process can be controlled by adjusting the culture conditions, such as the type of growth factors and signaling molecules used.

Question 3

Blastocyst stage

Answer 3

The blastocyst stage is a developmental stage of an embryo that occurs approximately 4-5 days after fertilization in mammals, including humans. At this stage, the embryo consists of a hollow ball of cells called the blastocyst.

The blastocyst is composed of two distinct cell populations: the inner cell mass (ICM) and the outer layer of cells called the trophectoderm. The ICM is the group of cells that will eventually develop into the fetus, while the trophectoderm will give rise to the placenta and other supporting tissues.

Question 4

What are the different kinds of pathogenic human genetic variants?

Answer 4

See pic

Question 5

Transition point mutation

Answer 5

involves the substitution of a purine nucleotide (adenine or guanine) for another purine nucleotide, or the substitution of a pyrimidine nucleotide (cytosine or thymine) for another pyrimidine nucleotide.

Question 6

Transversion point mutation

Answer 6

Transversion mutations involves the substitution of a purine nucleotide for a pyrimidine nucleotide or vice versa.

Question 7

Why is genome editing with programmable nucleases such as ZFN, TALEN, Cas 9 challenging?

Answer 7

NHEJ is the primary dsDNA repair pathway: Repair of double-strand breaks primarily result in gene disruption / indels but also chromosomal rearrangements and abnormalities

HDR with donor template works sometimes but very inefficient in most of cell types, there is also challenge with donor DNA delivery to the tissue, limiting clinical applications