Ever wonder why a person can look more like their mother or more like their father when they receive copies of both parents’ genes? Researchers from Cold Spring Harbor have conducted an investigation into this genomic query, and have found that the reason is random.
Both parents contribute one set copy of each gene to their offspring, which is called an allele. Each individual thus has two copies for each given trait (such as hair color or eye color), one coming from each parent. Both alleles are “switched” on and off as an embryo develops, bouncing between which trait will be expressed.
According to Cold Spring Harbor Laboratory, sometimes a cell will arbitrarily begin to use of one copy of a gene over the other when selecting traits. This activation of only one member of the gene pair, such as repeatedly selecting the mother’s genes or father’s genes, is called “monoallelic gene expression.”
Professor David Spector led a team of researchers, including Mélanie A. Eckersley-Maslin, David Thybert, Jan H. Bergmann, John C. Marioni, and Paul Flicek published their study on monoallelic gene expression in Developmental Cell today. Their paper, “Random Monoallelic Gene Expression Increases upon Embryonic Stem Cell Differentiation,” reveals that the researchers found that the random phenomenon of monoallelic gene expression is “far more likely to be found in mature, developed cell types than in their stem cell precursors.”
“It is not deterministic in any way,” said Spector. “This significant amount of flexibility and randomness in gene expression is important for adaptation as a species evolves, but it is unclear how it functions in organisms today.”
Professor Spector and his crew teamed up with researchers from the European Molecular Biology Laboratory, and together they used advanced sequencing technology to determine allele usage in two different cell types – embryonic stem cells, which can change or differentiate into any kind of tissue, and cells that had already differentiated into the beginning stages of neurons. Their research found that there as 5.6 times as many monoallelically expressed genes in the differentiated cells as there were in the embryonic stem cells.
Cold Spring Harbor Laboratory in Nassau County is home of leading biomedical research, and is world-renowned for its research in molecular biology and genetics.
[Source: Cold Spring Harbor Laboratory]
Image and description courtesy of Cold Spring Harbor Laboratory: The nucleus of every cell in our body contains two copies of each gene, encoded in our DNA (nuclei outlined in purple, DNA for individual genes labeled in red). In general, these copies are used equally, but on occasion, the cell chooses to use just one (seen here in yellow/green). Today, researchers from CSHL have discovered that this truly random process, known as monoallelic gene expression, occurs during development, offering an unexpected glimpse of the significant variability in gene expression.