Twins are one of nature's biggest miracles.
Monozygotic twins (products of a single zygote) are strikingly similar in
appearance, making them a subject of awe all around the globe. Split from the
same zygote, they often possess similar physical characteristics, though some
differences may be observed.
One of the reasons why monozygotic twins do have
physical dissimilarities after birth is the impact of the intrauterine (the
condition inside the uterus) environment on both of them. Read on to find out
more about how this condition can change the physical aspects of twins.
Twin babies share identical genomes and have
similar physical characteristics; however, this fact is subject to change. To
assess what exactly causes a modification of characteristics, a group of
scientists used DNA methylation procedures.
DNA methylation, a chemical activity that affects genes and is responsible for
determining health and disease risks among individuals, has now helped
scientists shed light on the importance of intrauterine environment for both
dizygotic and monozygotic twins. DNA methylation patterns were examined in
sets, which revealed a stunning result- the early environmental condition
actually alters the epigenome, that is, causes chemical changes in an individual's
DNA and histone proteins.
team of researchers, for the first time, analyzed genome scaled DNA methylation
profiles of umbilical cord tissue and blood and placenta of both mono and
dizygotic twins to determine the difference in their epigenetic profiles. The
team discovered epigenetic profile changes even in identical twins at the time
of birth. Difference of intrauterine conditions like blood supply changes,
nutritional differences and even fetal position can largely impact the environmental
condition faced by a fetus while inside the uterus, contributing to its
physical difference compared to his twin.
Interestingly, the altered genes were known to be
responsible for growth, metabolism, cardiovascular and diabetic health, which
may be a powerful tool in future to determine the twin's susceptibility to a
particular ailment even before birth, and appropriately modifying the
intrauterine environment to prevent the gene modification that may have been
responsible for the occurrence of that particular ailment.