If a cell is fused with another cell, which of the following would be the best example of a trans-mechanism of epigenetic control?
Answer: A gene that is originally silenced in one cell but expressed in the other is silenced in the hybrid.
I hope this helps, Regards.
The trans-mechanism of epigenetic control can result from the fusion of cells, as seen when certain diets in mice alter DNA methylation. An example of gene imprinting, another form of epigenetic control, is seen in the Igf-2 allele where the paternal allele is expressed and the maternal allele is silent.
The fusion of cells can lead to a specific type of epigenetic control, termed trans-mechanism. This process is best exemplified in the case of the pseudoagouti offspring phenomenon in mice. When female mice are fed a specific diet, it alters the methylation processes of their DNA. As a result, a specific region in the agouti gene becomes hypermethylated which in turn leads to an increased proportion of pseudoagouti offspring.
Addressing the second part of your question, in the Igf-2, or the Insulin-like growth factor 2 gene, it is the paternal allele that is usually expressed while the maternal allele is imprinted and silenced. Imprinting is another form of epigenetic control where the activity of a gene is determined based on which parent the allele was inherited from.
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