Developmental & Reproductive Genetics

Question 1

What are Totipotent Stem Cells?

Answer 1

These are stem cells with the ability to turn into any cell in the human body and are not limited to a set amount when replicating

Question 2

What are multipotent stem cells?

Answer 2

These are cells that are limited in their ability to differentiate and can only specialize in one or more cell lines. Example includes adult stem cell

Question 3

What are pluripotent stem cells?

Answer 3

These are “True stem cells” that can develop into almost any cell but when it is no longer in its embryonic stage, they can only become specific types of cells
They can develop into specialized cells but not organs

Question 4

What are unipotent stem cells?

Answer 4

They can become specialized cells and proliferate but are very limited in ability. They can self renew however, making them perfect for burn treatments

They are quite time consuming.

Question 5

What is prenatal development?

Answer 5

This is the process whereby a baby develops from a single cell after conception into and embryo and later a fetus

Question 6

What are Teratogens?

Answer 6

A teratogen is any agent that causes an abnormality following fetal exposure during pregnancy.

Question 7

Give 5 examples of teratogens

Answer 7

Thaliomide
Cocaine
Alcohol
Cigarretes
Some Viruses

Question 8

What is the effect of teratogens?

Answer 8

Teratogens may affect the embryo or fetus in a number of ways, causing physical malformations, problems in the behavioral or emotional development of the child, and decreased intellectual quotient (IQ) in the child.

Question 9

What are birth defects?

Answer 9

When a particular structure is sensitive to damage, it is called Critical period.
Birth defects can result from faulty genes or environmental insult and the mostly develop during the embryonic period, these defects are more severe than those that occur during the fetal period

Question 10

What is Developmental Genetics?

Answer 10

It is the study of how instructions coded in the genes control and coordinate an organisms development from fertilization and ending with death.
It also involves studying the regulation of cell growths, differentiation and morphogenesis to form tissue organs and anatomy

Question 11

What is Cell determination?

Answer 11

This is the process by which portions of the genome are selected for expression in different embryonic cells. it occurs in totipotent, embryonic stem cells and is a result of asymmetric segregation of cytoplasmic determinants.
This process is responsible for assigning the fate of the cell.

Question 12

What is cell differentiation?

Answer 12

This is the process whereby the cell becomes specialized so that it can perform a specific function and it comes after cell determination. It is a result of differential gene expression and is responsible for the functional specialization of genes

Question 13

What is developmental potential(potency)?

Answer 13

This describes the range of different cell types a cell can become. The developmental potential of individual cells decreases as development proceeds up to when their fate is determined.

For each cell lineage, a master control gene activates a group of downstream genes and defines a lineage differentiation.

Question 14

What are cytoplasmic determinants?

Answer 14

These are maternal substances that regulate the expression of genes which can affect the developmental fate of the cell.

Question 15

What steps are involved in embryonic development?

Answer 15

It involves
pattern formation
axis specification and organogenesis

Question 16

Define pattern formation

Answer 16

This is a series of steps where differentiated cells are arranged spatially to form tissue and organs(induction)

Question 17

Define axis specification

Answer 17

This is is the first step in defining specific regions of the developing embryo. Embryos exploit asymmetries, either pre-existing in the egg or triggered by external cues, to establish embryonic axes. The axial information is then used to generate regional differences within the embryo.

Question 18

Explain briefly how interaction between neighboring cells are mediated to induce a response

Answer 18

There is contact between inducing and responding cells

Inducers diffuse from one cell to another

Matrix of one cell induces change in another cell

Question 19

What are the 4 major families of paracrine signaling molecules?

Answer 19

Fibroblast growth factor

Hedgehog family

Wingless (Wnt) family

Transforming growth factor beta (TGF-B) family

Question 20

Describe Fibroblast growth Factors?(FGFs)

Answer 20

These are widely expressed in developing bone and most common human autosomal disorders of generalized bone growth are caused by mutations in FGFs.

Abnormal bone growth is also a feature of a group of autosomal dominant disorders characterized by premature fusion (synostosis) of the cranial sutures, misshapen skulls and various limb defects

Question 21

Name 3 FGFR genes, and one craniosynostosis syndrome cause by mutations in those genes.

Answer 21

FGFR-1: Pleiffer syndrome

FGFR-2: Beare-Stevenson syndrome

FGFR-3: Crouzon syndrome

Question 22

Describe DNA transcription factor

Answer 22

This is a protein that controls the rate of transcription of genetic information from DNA to mRNA by binding to a specific DNA sequence.

Its major function is to regulate genes so that they are expressed in the right cell at the right time and in the right amount throughout the life of the cell.

They often regulate transcription of many genes and different developmental pathways to maintain developmental flexibilty and genomic economy

Mutations have pleiotropic effects