What factors might affect how similar or different a pair of identical monozygotic twins are? Such factors could include environmental influences, such as exposure to infection or diet, as well as other effects, such as somatic mutation, effects of aging, or epigenetic changes in gene expression in one twin compared with the other.
What factors influence identical twins?
Few specific genes in humans have been definitively linked with hyperovulation or an increased probability of DZ twinning. Other factors known to influence the chance of having DZ twins include the mother’s age, ethnic background, diet, body type, and number of other children .
What causes differences in monozygotic twins?
DNA replication errors during cell division cause monozygotic twins to diverge from each other even during the earliest stages of development, a new study finds.
What could cause identical twins to have differences in their characteristics?
Environmental Differences
While identical twins form with the same set of genes, human development is not just genetic. 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.
Is the similarity of monozygotic twins due to genetic factors alone?
Abstract. It is generally assumed that the identity of the genotype explains why there is less difference between monozygotic than between dizygotic twins. But monozygotic twins are also exposed to identical non-genetic influences , which act on the common zygote until the time of separation into the two twin partners.
How does the environment affect identical twins?
Because identical twins share all of their genes, their measurements of IQ and sleep time will be more similar the bigger role genes play in it (i.e., differences between two identical twins must be caused by the environment because their genes are the same ).
Monozygotic twins are immune to the effects of recessive genetic mutations. Monozygotic twins, also called fraternal twins, share 50% of their genetics . Monozygotic twins, also called identical twins, share 100% of their genetics. 7.
Which factor represents a possible cause for monozygotic twinning?
Such factors could include environmental influences , such as exposure to infection or diet, as well as other effects, such as somatic mutation, effects of aging, or epigenetic changes in gene expression in one twin compared with the other.
Can monozygotic twins look different?
They may have different lifestyles – exercise, smoking, drinking, nutrition, job stress, etc. As identical twins get older they may look more and more different, because they are exposed to more diverse environments . The science of epigenetics explains how these environmental influences can affect the genes.
How can you tell the difference between identical twins?
| Identical Twins Fraternal Twins | A single zygote splits into two parts and develops into different embryos. Two eggs are fertilized by two different sperms. |
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Why an older identical twin pair differs more significantly than a younger identical twin pair?
Statistical analysis suggested that older twin pairs were more epigenetically different than younger twins. It also revealed that twins who reported having spent less time together during their lives, or who had different medical histories, had the greatest epigenetic differences .
What characteristics do identical twins have?
Identical twins are always the same sex; they usually are the same height, weight and have similar hair color . In relation to the genetic differences in MZ twins, different genes can be turned on or off which is why one identical twin may have a condition or disease that the other doesn’t.
Why do monozygotic twins have different phenotypes quizlet?
They may have different phenotypes because of differences in their environments , such as nutrition and healthcare. Why might genetically identical twins have different phenotypes? List three patterns of inheritance that are different than the dominant-recessive pattern of Mendel’s peas.
Which can you find a high genetic differences in monozygotic twins or dizygotic twins?
Abstract. Monozygotic twins are essentially genetic copies. Greater phenotypic concordance between monozygotic twin pairs compared to dizygotic pairs is taken as evidence of an underlying genetic contribution.
Why do identical twins have a higher concordance rate than non identical twins?
This line of thinking has some legitimacy. Since MZ twins are genetically identical, as compared with DZ twins who only share, on average, half of their genomes, a greater concordance rate, that is, a greater phenotypic similarity, in MZ twins than in DZ twins is likely due to greater genetic similarity .
What are some challenges twins might face?
- Difficult Pregnancy. Tetra Images / Getty Images. ...
- Lack of Sleep. Annmarie Young Photography/Moment/Getty Images. ...
- Finding One-on-One Time. ...
- Logistics. ...
- The Squabbling. ...
- Being Fair and Equal. ...
- Individuality. ...
- Mess.
Will identical twins raised in different environments have the same traits?
When an environmental influence is dominant, the trait similarity would be the same for identical and fraternal twins . The researchers found that both genetic and environmental factors influenced glucose metabolism in the brain, but they predominantly affected different areas.
How do genetics influence twins?
Some women have versions (called alleles) of these genes that make them more likely to hyperovulate . This means there is a higher chance that two eggs could get fertilized at once, leading to fraternal twins. The gene versions that increase the chance of hyperovulation can be passed down from parent to child.
What are the three different cases for monozygotic twins?
These are called monochorionic/diamniotic twins. Sixty to 65 percent of identical twins are monochorionic/diamniotic. Monozygotic twins sharing one placenta and one sac are called monochorionic/monoamniotic twins. Finally, monozygotic twins that are monochorionic/monoamniotic can be conjoined.
What percentage of their genes do monozygotic twins have in common?
Identical, or monozygotic (MZ), twins have 100 percent of their genes—including those that influence risk for alcoholism—in common, whereas fraternal, or dizygotic (DZ), twins share (on average) only 50 percent of the genes that vary in the population (see figure). Common Environmental Sources.
How do monozygotic twins develop?
To form identical or monozygotic twins, one fertilised egg (ovum) splits and develops into two babies with exactly the same genetic information . To form fraternal or dizygotic twins, two eggs (ova) are fertilised by two sperm and produce two genetically unique children.
Do monozygotic twins have the same genotype?
Monozygotic or identical twins occur when a fertilized egg splits apart in the first two weeks of development. The result is the creation of two separate, but genetically identical offspring. That is, they possess the same genotype and often the same phenotype.
Do monozygotic twins have the same fingerprints?
Close but not the same
It’s a misconception that twins have identical fingerprints. While identical twins share many physical characteristics, each person still has their own unique fingerprint.
Which of the following describes the way in which monozygotic twins occur?
Which of the following describes the way in which monozygotic twins occur? The egg is fertilized by a single sperm and then splits completely into two separate zygotes.
Can identical twins grow at different rates?
Twin to Twin Transfusion Syndrome (TTTS) is a prenatal condition in which twins share unequal amounts of the placenta’s blood supply resulting in the two fetuses growing at different rates . 70% of identical twins share a placenta, and 15-20% of these pregnancies are affected by TTTS.
What confusion can be created if the twins are identical?
Answer: Parents of twins and twins themselves are often confused about their zygosity . It is human nature to look for differences, hence twins and/or their parents may think they are not identical when they very well could be.
Why are identical twins exactly similar while fraternal twins are dissimilar?
Fraternal twins are “dizygotic,” meaning that they developed from two different eggs fertilized by two different sperm cells, while identical twins are “monozygotic” i.e., they developed from a single fertilized egg that split .
Can identical twins have different eye colors?
The possibility of identical twins having different eye colors is extremely rare . Fraternal twins (developing from 2 separate sets of egg and sperm) however can most definitely have different eye colors as they only share about 50% of their DNA with their twin, just like any other siblings do.
Why is it particularly useful to study identical twins who were raised in different environments?
Why is it particularly useful to study identical twins who were raised in different environments? It is possible that high concordance rates between identical twins reared together is due to their being treated more similarly than nonidentical twins .
Is it possible that the twins would have different changes and development Why?
Identical twins have identical genes, because they are born of an embryo that splits at a very early stage in development. Such twins are often indistinguishable in outward appearance. But over the course of time they may experience radically dissimilar health .
Why do some twins not look alike?
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 identical twins marry identical twins?
Their babies are cousins, but genetically they are brothers. Identical twins Briana and Brittany, 35, married identical twins Josh and Jeremy Salyers, 37 , and now they’re introducing the world to their babies, who are so genetically similar that the cousins are more like brothers.
Why can monozygotic twins have different phenotypes?
Identical or monozygotic twins occur when a single egg is fertilised to form 1 zygote that divides into 2 separate embryos. As a result, identical twins share identical DNA but may show differences in their phenotype due to environmental factors .
How is it possible for offspring to have different phenotypes from their parent even when 1 self fertilization occurs 2 there is no crossing over and 3 no mutation occurs?
How is it possible for offspring to have different phenotypes from their parent, even when 1) self-fertilization occurs, 2) there is no crossing over, and 3) no mutation occurs? Offspring can be homozygous at genes where parents are heterozygous . Gametes from different individuals combine to produce offspring.
What is the process of crossing two individuals that are not genetically alike?
Crossing two genetically different individuals. Hybridization .
What factors influence identical twins?
Few specific genes in humans have been definitively linked with hyperovulation or an increased probability of DZ twinning. Other factors known to influence the chance of having DZ twins include the mother’s age, ethnic background, diet, body type, and number of other children .
