Human bodies differ from one another. For an unborn offspring, there are many factors affecting its phenotype, including the s given by its mother and father or possible hereditary traits from a relative via associated pedigree. Each person normally has two copies of each gene (s) - one given by his/her one mother and the other given by the father. These can be either identical, in which case they are referred to as to as homozygous, or different (referred to as heterozygous). Furthermore, alleles can be either dominant or recessive. For heterozygous genotypes, this is manifested in either Bb or bB (order is important due to lineage of alleles from parents), so that both a dominant and recessive allele of a gene is present. Differently for …show more content…
Since it is possible to find out about our genes, pedigree and test-crossing can be used to provide one’s genetic information, such as inherited disease and disorders. For example, fish odor syndrome occurs when a person inherits two copies of a defective allele, a largely negative mutation from the original gene. In this case, these defective alleles had to come from both the father and mother; but since they both may only have one copy of defective allele, they may not actually suffer from the disease. Therefore, one can avoid these situations from arising by using pedigree and determining the likelihood of an offspring having a specific disease. On the other hand, the test-cross tool detects if the alleles given by both the mother and father are identical of different. Since a person can have either homozygous or heterozygous genotype, and chances of getting a dominant trait is not relative to whom it came from, the phenotype of offspring depends on the dominancy of the allele. Some traits that are inherited by offspring can be dominated by a single allele. Thus, there is a possibility that the offspring completely inherits its phenotype either from the mother or father, despite receiving two alleles in
Twin studies have been used to distinguish between genetic and environmental factors for many disorders in the general population including ectodermal dysplasia, Ellis-van Creveld, and anencephaly. This review focuses on genetic disorders affecting monozygotic, dizygotic, and conjoined twins to gain a better understanding of them. Many studies focus on twins because they have a nearly identical genome, which eliminates environmental factors. In case studies, the concordance rates in monozygotic twins have supported that certain disorders were caused by genetics and not the environment. The discordant values in twins will also be evaluated briefly. Twinning studies have also shown linkages between specific disorders and the genes responsible for them. Knowing the location of these genes allows patients to be treated quickly and efficiently. This paper will discuss the possible causes of twinning and the various methods of identifying abnormalities in twins. These methods also allow preventive measures against the rise of birth defects during prenatal development. Epigenetics in twins is also viewed through the perspective of effects on them. Treatments for genetic disorders in twins are reviewed, ranging from the restoration of malformed teeth to the separation of conjoined twins. Support groups for twins in treatment, and their families are also briefly reviewed.
Introduction In our genes, multiple different alleles determine whether one person will have a certain trait or not. Alleles are what make up our genotypes and in this lab, we wanted to determine the genotypes of our class in the two loci: TAS2R38 and PV92. The TAS2R38 locus codes for a protein that involves the bitter taste of PTC; the gene determines whether or not a person will taste the PTC paper as very bitter or no taste at all. People with the “T” allele are tasters, while those that are homozygous recessive (tt) are non-tasters. The taster locus can be found in chromosome 7.3.
An individual can be homozygous dominant (two dominant alleles, AA), homozygous recessive (two recessive alleles, aa), or heterozygous (one dominant and one recessive allele, Aa). There were two particular crosses that took place in this experiment. The first cross-performed was Ebony Bodies versus Vestigle Wings, where Long wings are dominant over short wings and normal bodies are dominant over black bodies. The other cross that was performed was White versus Wild where red eyes in fruit flies are dominant over white eyes. The purpose of the first experiment, Ebony vs. Vestigle was to see how many of the offspring had normal bodies and normal wings, normal bodies and vestigle wings, ebony bodies and normal wings, and ebony body and vestigle wings.
Advantages of genetic testing may be helpful in determining whether or not you have a disease or are proba...
In parentage testing, genetic markers from a child are identified and compared to the alleged parent or parents. According to Ostrowski (2003) every person has a series of genetic systems, or loci. Within each genetic system there is a pair of alleles. Half of the alleles come from the mother and half from the father. Once these alleles are extracted, amplified, and identified, they are used in a set of equations to identify three parentage indices. These indices are the paternity index, probability of paternity, and the probability of exclusion. Harmening (2005) suggests that the calculations are only valid if the tested man is compared to a “random man” that is not biologically related to him. Also, the equations must be based off of accurate gene frequencies for each genetic system and the population must be of similar ethnic background.
By using identified gene mutations that are known to cause diseases, asymptomatic individuals are able to discover if they are at risk for specific genetic conditions; this is known as genetic testing. Unfortunately, genetic testing can vary in its predictive ability. For example, Huntington disease, Duchenne Muscular Dystrophy, Fragile X syndrome and multiple endocrine neoplasia type 2 are conditions that can be determined by genetic testing (Samen, 1996). In contrast, for multifaceted diseases like Alzheimer’s, breast and ovarian cancer and colorectal cancer, predisposition can be determined with genetic testing. However, an absolute diagnosis of those diseases cannot be made (Heshka et al., 2008).
A genetic family history assessment contains information about family structure and relationships. A typical nurse will use a three-generation family pedigree to gather the information. By doing so, nurses can be aware of which family members are at risk for disorders from a genetic component. Therefore, they can be provided with lifestyle advice, recommendations, and referrals to appropriate specialists (Kaakinen, Coehlo, Steele, Tabacco & Hanson, 2015). A genetic family history assessment will be provided about my family.
The exercise involved a series of ‘mating’ events resulting in 6 generations. Each mating event produced offspring with ‘possible’ newly inherited traits. The idea of ‘chance’ was included through simple coin tosses. Also, ideas of selection and mutations were introduced into the ‘gene pool’, which presented a deeper and more clear understanding of Mendelian inheritance and the Hardy-Weinberg equilibrium. Upon reaching the third generation, A B1 mutant allele was introduced to the blue locus-influencing fin shape and a G1 mutant allele was introduced to the green locus-influencing Mouth
There are many types of genetic tests that are administered to the adult population. The more commonly used genetic tests are paternity tests, genealogical tests, and forensic testing. They are quite self-explanatory; paternity tests are to determine relatedness of 2 subjects, genealogical tests are used to formulate a heritage or ancestry, and forensic testing is used to identify or rule out a person that has been charged with a crime. Other genetic tests include presymptomatic testing, used to determine the risk someone has to developing a genetic disorder, diagnostic screening, used to rule out or identify a suspected condition, and carrier screening, used to determine if an individual carries one copy of a gene mutati...
The study of the causes of substance abuse has been conflicting many people for a long time. There are two causes of substance abuse that have been argued for many years. The first cause is believed to be environmental. The second cause is a genetic cause that leads people to turn to drugs and alcohol. In “Touch of Grey” Lanthrop comes to the conclusion that his substance abuse issue posses both genetic and environmental causes. This argument is specifically compelling because he uses research and a personal statement to prove his findings. While environmental issues have a large impact on substance abuse, genetics have the greatest impact on substance abuse.
A genetic test can help a person prepare for the future. For instance, if a couple wanted to have kids and they knew a disease like sickle cell ran in the family they may consider getting a genetic test. They would be able to find out whether or not they ar...
The desire to have a "normal" child is held by every parent and only now are we beginning to have the ability to select for that child. In preparation to receiving genetic testing, the parents are required to meet with a genetic counselor. A detailed description of the testing methods are reviewed with the couple as well as the risks which are involved with each. Upon an understanding of the procedures, the counselor discusses the many possible outcomes which could be the result of the diagnosis. Finally, before any tests are performed, anxieties from either of the parents are addressed as well as the psychological well-being of the parents.
This paper addresses a currently relevant topic of detection of associations of copy number polymorphism with traits and will be of interest to readers of Genetics Research.
In the twin study method, researchers studies identical twins (monozygotic twins) and fraternal twins (dizygotic twins) to determine how much they resemble each other on a variety of characteristics. Identical twins have exactly the same genes because a single sperm cell of the father fertilizers a single egg of the mother, forming a cell that then splits and forms two human beings-"carbon copies." But fraternal twins are no more alike genetically than any two siblings born in the same parents. In the case of fraternal twins, two separate sperm cells fertilize two separate eggs that happen to be released at the same time during ovulation.
I have always been fascinated by conjoined twins and have always had questions about them like; what do the Siamese have to do with conjoined twins? Why does this form of twin happen? What, if any genes cause this? What types of Conjoined twins are there? How does the environment affect, if at all, the biological families' gene pool? In my research in efforts to prepare this paper, I found the answers to this question and many more. This term paper will cover the types of conjoined twins, the biological occurrence that causes conjoined twins, a look into some of the genetic and environmental causes of conjoined twins, the types of conjoined twins and the genetic and social impact of conjoined twins.