This is a study of the biological system of epigenetics. Every cell in our body has the same genetics, or library of information contained in the form of DNA sequence. Epigenetics is the system that controls how this DNA is used in a particular situation, or what books are opened and read. During embryonic development, cells know what they want to become, e.g., a muscle cell, and, once they take on an identity, remember that they are when they duplicate themselves during growth. Epigenetics does ....This is a study of the biological system of epigenetics. Every cell in our body has the same genetics, or library of information contained in the form of DNA sequence. Epigenetics is the system that controls how this DNA is used in a particular situation, or what books are opened and read. During embryonic development, cells know what they want to become, e.g., a muscle cell, and, once they take on an identity, remember that they are when they duplicate themselves during growth. Epigenetics does not achieve this through changing genetics the library always stays intact. Rather, it acts by using proteins or chemicals to make DNA functional in one way, or another. Genomic imprinting is a special type of epigenetics. While an embryo has received identical genetic information from each of its parents, the epigenetic information received from each parent was not entirely the same. Some genes which behave differently according to what parent they came from. For example, a gene that makes a growth factor protein is active only if received from the father. If received from the mother, it is inactive, and makes no protein. Genes behaving in this way are known as imprinted genes. We are trying to discover what epigenetic mechanisms are behind this behaviour of imprinted genes. One way we are approaching this problem is to study germ cells the cells giving rise to eggs and sperm. These cells are unusual in that their imprinted genes behave in the same way regardless of whether they were received from the mother or father, i.e., like any other gene. If we can understand why this is the case, we will be better able to understand why imprinted genes behave the way they do in the rest of the cells of the body. Broadly, the mechanisms we uncover should further our understanding of germ cell development, gene expression, and disease. Perturbations in the epigenetic profile are likely causes of human disease, including cancer.Read moreRead less
The Establishment Of Epigenetic Marks At Metastable Epialleles In The Mouse
Funder
National Health and Medical Research Council
Funding Amount
$372,750.00
Summary
Occasionally, identical twins are found to have distinctly different characteristics, such as eye colour or severity of genetic disease, that clearly cannot be explained by their genetic makeup, and are unlikely to be the result of environmental differences. In genetically identical mice, similar cases exist, where some mice have a yellow coat and others a brown coat. In instances such as these, a growing body of evidence suggests that certain modifications to genes are responsible. These modifi ....Occasionally, identical twins are found to have distinctly different characteristics, such as eye colour or severity of genetic disease, that clearly cannot be explained by their genetic makeup, and are unlikely to be the result of environmental differences. In genetically identical mice, similar cases exist, where some mice have a yellow coat and others a brown coat. In instances such as these, a growing body of evidence suggests that certain modifications to genes are responsible. These modifications are not traditional DNA mutations, but are chemical modifications of the basic sequence. Currently, we do not know when these DNA modifications are established during foetal development. We will use the mouse coat colour gene mentioned above to investigate when the different physical characteristics are established in embryonic development. Indeed, there is increasing evidence that critical periods exist in human foetal development where minor environmental or nutritional changes can affect long-term health of the adult. Perhaps the establishment of the DNA modifications are under an environmental or nutritional influence. Further study of when and how the DNA modifications are set-up during embryonic development is necessary in order to understand these events.Read moreRead less
A Random Mutagenesis Screen To Identify Modifiers Of Epigenetic Phenomena In The Mouse.
Funder
National Health and Medical Research Council
Funding Amount
$680,750.00
Summary
In recent months, both the human and mouse genome projects have been completed. The main focus now for mammalian geneticists is to discover the function of the genes sequenced in these initiatives. One way to achieve this goal is by random mutagenesis followed by screening of mice for novel phenotypes. In the mouse, ethylnitosourea (ENU) is a chemical that can be used to perform the mutagenesis. ENU causes mutations in sperm. We are using ENU mutagenesis to search for genes that modify epigeneti ....In recent months, both the human and mouse genome projects have been completed. The main focus now for mammalian geneticists is to discover the function of the genes sequenced in these initiatives. One way to achieve this goal is by random mutagenesis followed by screening of mice for novel phenotypes. In the mouse, ethylnitosourea (ENU) is a chemical that can be used to perform the mutagenesis. ENU causes mutations in sperm. We are using ENU mutagenesis to search for genes that modify epigenetic states. Epigenetic modifications are alterations in the genome that do not change the DNA sequence, yet silence the expression of genes. Silencing occurs on a cell-by-cell basis within a tissue resulting in mosaic expression. Silencing can also occur between individuals of the same genetic makeup. For example, identical twins are occasionally found that have distinctly different characteristics, such as eye colour or severity of genetic disease. These differences may be the result of variable epigenetic modifications. However, very little is known about how these variable epigenetic modifications are controlled. We wish to find the proteins involved in establishing and maintaining epigenetic states. It is likely that these processes play a fundamental role in the determination of phenotype, both in normal development and disease.Read moreRead less