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Can identical twins have phenotypic differences?
Identical twins share the same genotype, since their genomes are identical; but they never have the same phenotype, although their phenotypes may be very similar. This is apparent in the fact that close relations can always tell them apart, even though others might not be able to see the subtle differences.
How is it possible for cells to be genetically identical but have different phenotypes?
This is because all cells in the body have the same genome but do not have the same epi-genome which controls gene expression. This will make cells to have different gene expression profiles which eventually will make cells to take different fates.
Are there any ways identical twins can be different genetically?
SAN FRANCISCO – Identical twins may not be so identical after all. Even though identical twins supposedly share all of their DNA, they acquire hundreds of genetic changes early in development that could set them on different paths, according to new research.
Why are genetically identical twins not always phenotypically identical?
DNA Differences Identical twins do indeed start with identical DNA—they are the result of the same sperm from dad and the same egg from mom. The original fertilized egg divides one or more times before the resulting clump of cells splits into two. Each clump of cells goes on to become one of the identical twins.
What would be some obvious differences that could be observed in identical twins?
Some identical twins can have different heights and weights. This is because height and weight are controlled by what you eat as well your DNA. Differences in diet can start earlier than you might imagine. When the twins are growing inside the uterus, there can be differences in how well they connect to the placenta.
Can identical twins be allergic to different things?
Are identical twins allergic to the same things? A. Not necessarily, though there is a strong genetic component in allergy. Identical twins, who inherit identical genes, tend to be far more similar in their allergies than siblings or fraternal twins, who develop from two embryos, not one.
How can two organisms have the same phenotype but different genotypes?
Same phenotype but different genotype is possible due to presence of dominant allele. A person can have a dominant allele on both the homologous chromosomes (i.e. in double dose) while another person may have single dominant allele and a corresponding recessive allele.
What are phenotypic differences?
An organism’s phenotype results from two basic factors: the expression of an organism’s genetic code, or its genotype, and the influence of environmental factors. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic.
How can identical twins who share identical genes have different behaviors?
The researchers thus concluded that the mice’s divergent experiences of their environment were driving their brain changes. Thus identical twins, though they start with the same genes, likely develop different personalities in the same environment partially based on how they interact with their environment.
How do identical twins differ from one another?
While identical twins form with the same set of genes, human development is not just genetic. The environment also has an impact. So, beginning in the early environment of the womb, external influences can change the appearance of twins. For example, some monozygotic twins share a placenta.
Why are monozygotic twins so similar?
Human monozygotic twins and other genetically identical organisms are almost always strikingly similar in appearance, yet they are often discordant for important phenotypes including complex diseases. Such variation among organisms with virtually identical chromosomal DNA sequences has largely been attributed to the effects of environment.
Are genetically identical MZ twins raised in the same environment?
This study design allows comparisons between genetically identical MZ twin pairs who have been raised in a shared environment, at least as similar as for any two siblings, and those who have been raised in different homes, cities and states.
Can the environment affect the appearance of twins?
The environment also has an impact. 1 So, beginning in the early environment of the womb, external influences can change the appearance of twins. For example, some monozygotic twins share a placenta.