Humans, chimpanzees and monkeys share DNA but not gene regulatory mechanisms
Humans,
chimpanzees and monkeys share DNA but not gene regulatory mechanisms
Posted by: Deepak Kumar
Humans share over 90% of their DNA with their primate cousins. The
expression or activity patterns of genes differ across species in ways that
help explain each species' distinct biology and behavior.
DNA factors that contribute to the differences were described on Nov. 6
at the American Society of Human Genetics 2012 meeting in a presentation.
Dr. Gilad reported that up to 40% of the differences in the expression or
activity patterns of genes between humans, chimpanzees and rhesus monkeys can
be explained by regulatory mechanisms that determine whether and how a gene's recipe
for a protein is transcribed to the RNA molecule that carries the recipe
instructions to the sites in cells where proteins are manufactured.
In addition to improving scientific understanding of the uniqueness of
humans, studies such as the investigation conducted by Dr. Gilad and colleagues
could have relevance to human health and disease.
"Through inter-species' comparisons at the DNA sequence and
expression levels, we hope to identify the genetic basis of human specific
traits and in particular the genetic variations underlying the higher
susceptibility to certain diseases such as malaria and cancer in humans than in
non-human primates," said Dr. Gilad.
Dr. Gilad and his colleagues studied gene expression in lymphoblastoid
cell lines, laboratory cultures of immortalized white blood cells, from eight
humans, eight chimpanzees and eight rhesus monkeys.
They found that the distinct gene expression patterns of the three
species can be explained by corresponding changes in genetic and epigenetic
regulatory mechanisms that determine when and how a gene's DNA code is
transcribed to a messenger RNA (mRNA) molecule.
Dr. Gilad also determined that the epigenetics process known as histone
modification also differs in the three species. The presence of histone marks
during gene transcription indicates that the process is being prevented or
modified.
"These data allowed us to identify both conserved and
species-specific enhancer and repressor regulatory elements, as well as
characterize similarities and differences across species in transcription
factor binding to these regulatory elements," Dr. Gilad said.
Among the similarities among the three species were the promoter regions
of DNA that initiated transcription of a particular gene.
In all three species, Dr. Gilad's lab found that transcription factor
binding and histone modifications were identical in over 67% of regulatory
elements in DNA segments that are regarded as promoter regions.
The researchers presentation is titled, "Genome-wide comparison of
genetic and epigenetic regulatory mechanisms in primates."
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The above story is based on materials provided by American Society of
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