Can identical twins be different from each other?
Research published on January 7 in the journal Nature Genetics shows that identical twins differ by an average of 5.2 genetic mutations. The authors argue that these small differences between twins’ genetic code could change how scientists study human development.
Can a boy and girl twin be in the same sac?
Identical, or monozygotic, twins may or may not share the same amniotic sac, depending on how early the single fertilized egg divides into 2. If twins are a boy and a girl, clearly they are fraternal twins, as they do not have the same DNA. A boy has XY chromosomes and a girl has XX chromosomes.
Can fraternal twins be identical?
Yes, it is possible for same-sex fraternal twins to look extremely similar. Like any siblings, fraternal twins are the products of two separately fertilized eggs from the same mother and father. They are genetically as similar as other non-twin siblings.
Why can fraternal twins be different genders?
In 99.9% of cases boy/girl twins are non-identical. However, in some extremely rare cases resulting from a genetic mutation, identical twins from an egg and sperm which began as male (XY) can develop into a male / female pair.
Can a male twin have twins?
One of them inherits the gene for hyperovulation. The male twin does not have twins, but he passes the gene for hyperovulation to his daughter. Generation 3: The daughters who inherited the gene for hyperovulation give birth to twins.
How do some fraternal twins look identical?
Since fraternal twins are the result of different eggs and different sperm, they share the same percentage of chromosomes as any other siblings. The National Human Genome Research Institute says that this is about 50 percent. This is why they don’t look exactly alike and can be assigned different sexes at birth.
Can you have different gender identical twins?
Female and male identical twins Sometimes identical twins can be assigned the sex of male and female at birth. These twins start off as identical males with XY sex chromosomes. But shortly after the egg divides, a genetic mutation called Turner syndrome occurs, leaving one twin with the chromosomes X0.
Can fraternal twins be different genders?
Fraternal twins may be the same gender, they may have many of the same characteristics, but also may be very different from each other and, in fact, share half of their genes just like their sisters and brothers.