Suppose the couple who went for CF screening received different results. The res

Question

Suppose the couple who went for CF screening received different results. The results of the testing revealed that the man and woman both are carriers for the CF allele. a/ genotype of man b/ genotype of woman c/ type of sperms the man can make d/ type of eggs the woman can make e/ Draw a Punnett square to determine the types of children f/ Circle the genotype of the CF child in the Punnett square. What is the chance of their having a CF child? g/ what is the chance that they will have a child that is a carrier?

Explanation / Answer

Man: f_a_ Female: FFAA Since he has flat feet and no freckles, he is ffaa. The genotypes that his gametes will have is fa and fa. The womans genotype is FA and FA. Make a punnet square. Female:.....FA.......FA M A.....fa.......FfAa.....FfAa L E.....fa......FfAa......FfAa The genotypes that their children would have is FfAa and the phenotype is that they will all have freckles and normal feet. The term sperm is derived from the Greek word (sp??µa) sperma (meaning "seed") and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. All living things reproduce. Reproduction — the process by which organisms make more organisms like themselves — is one of the things that sets living things apart from nonliving matter. But even though the reproductive system is essential to keeping a species alive, unlike other body systems, it's not essential to keeping an individual alive. In the human reproductive process, two kinds of sex cells, or gametes, are involved. The male gamete, or sperm, and the female gamete, the egg or ovum, meet in the female's reproductive system to create a new individual. Both the male and female reproductive systems are essential for reproduction. The female needs a male to fertilize her egg, even though it is she who carries offspring through pregnancy and childbirth. Humans, like other organisms, pass certain characteristics of themselves to the next generation through their genes, the special carriers of human traits. The genes that parents pass along are what make their children similar to others in their family, but also what make each child unique. These genes come from the male's sperm and the female's egg. Most species have two sexes: male and female. Each sex has its own unique reproductive system. They are different in shape and structure, but both are specifically designed to produce, nourish, and transport either the egg or sperm. “Eggs” are produced in the ovaries, BUT these are not "true eggs" yet, and will never complete meiosis (a special type of cell division) and become "true eggs" unless OR until they are first fertilized by a sperm. Within the ovary, a follicle consists of one potential egg cell surrounded by special cells to nourish and protect it. HOW MANY EGGS DOES A WOMAN ACTUALLY HAVE? A human female typically has about 400,000 follicles/potential eggs, all formed before birth. Only several hundred (about 480) of these “eggs” will actually ever be released during her reproductive years. Normally, in humans, after the onset of puberty, due to the stimulation of follicular-stimulating-hormone (FSH) one “egg” per cycle matures and is released from its ovary. One month the left ovary will release a potential egg and the next month the right ovary will release a potential egg. First off, your husband's chances of being a carrier are roughly 1 in 25 if he is of european descent. I mean if he's 'white' if that's not clear enough, I don't want to be confusing. IF and only IF he is a carrier, then there is a 1-4 chance of your baby having cystic fibrosis. So right now, there's something like a 1% chance of your baby being affected. That will jump to 25% of your husband is a carrier. My cousin died of cystic fibrosis about 5 years ago. She was 21. Life expectancy used to be in the mid-teens for CF affected children, it is increasing. It is _possible_ that by the time our children are in their 30's, the lifespan will have been pushed back much further - but its not for certain. If your baby has CF, you should begin managing the disease _immediately_. Personally I would suggest prenatal testing if your husband is a carrier. While some parents opt to terminate pregnancies if the child is a carrier, even if you won't, I think its best to know before birth, so you can be a little more 'ready'. One impact of CF is that affected children have trouble getting nutrition. (The more obvious impact is a continual build up of fluid in the lungs). My cousin was very petite - likely because of the nutritional issues. Before she died, she received a partial lung transplant from her father and brother, which unfortunately never really took. They now give children with CF some kind of medication to help them with their nutrition. I still belive if she'd been physically larger and stronger - which she might have been with current medicine - she might have been able to take the transplant better. Good luck to you. When my wife and I were pregnant with our first, we had exactly the same experience - I was a carrier, she tested while pregnant and found she was also a carrier, which might for quite a stressful pregnancy. Thankfully, our daughter is only a carrier - like us. I hope it turns out well for your family. Final piece of advice, from my aunt, is that she urged everyone in our family to do 'whatever we had to' to not have a child with CF. We can only imagine what its like, she's lived through it. When a genetic disorder is diagnosed in a family, family members often want to know the likelihood that they or their children will develop the condition. This can be difficult to predict in some cases because many factors influence a person’s chances of developing a genetic condition. One important factor is how the condition is inherited. For example: Autosomal dominant inheritance: A person affected by an autosomal dominant disorder has a 50 percent chance of passing the mutated gene to each child. The chance that a child will not inherit the mutated gene is also 50 percent (illustration). Autosomal recessive inheritance: Two unaffected people who each carry one copy of the mutated gene for an autosomal recessive disorder (carriers) have a 25 percent chance with each pregnancy of having a child affected by the disorder. The chance with each pregnancy of having an unaffected child who is a carrier of the disorder is 50 percent, and the chance that a child will not have the disorder and will not be a carrier is 25 percent (illustration). X-linked dominant inheritance: The chance of passing on an X-linked dominant condition differs between men and women because men have one X chromosome and one Y chromosome, while women have two X chromosomes. A man passes on his Y chromosome to all of his sons and his X chromosome to all of his daughters. Therefore, the sons of a man with an X-linked dominant disorder will not be affected, but all of his daughters will inherit the condition (illustration). A woman passes on one or the other of her X chromosomes to each child. Therefore, a woman with an X-linked dominant disorder has a 50 percent chance of having an affected daughter or son with each pregnancy (illustration). X-linked recessive inheritance: Because of the difference in sex chromosomes, the probability of passing on an X-linked recessive disorder also differs between men and women. The sons of a man with an X-linked recessive disorder will not be affected, and his daughters will carry one copy of the mutated gene (illustration). With each pregnancy, a woman who carries an X-linked recessive disorder has a 50 percent chance of having sons who are affected and a 50 percent chance of having daughters who carry one copy of the mutated gene (illustration). Codominant inheritance: In codominant inheritance, each parent contributes a different version of a particular gene, and both versions influence the resulting genetic trait. The chance of developing a genetic condition with codominant inheritance, and the characteristic features of that condition, depend on which versions of the gene are passed from parents to their child (illustration). Mitochondrial inheritance: Mitochondria, which are the energy-producing centers inside cells, each contain a small amount of DNA. Disorders with mitochondrial inheritance result from mutations in mitochondrial DNA. Although these disorders can affect both males and females, only females can pass mutations in mitochondrial DNA to their children. A woman with a disorder caused by changes in mitochondrial DNA will pass the mutation to all of her daughters and sons, but the children of a man with such a disorder will not inherit the mutation (illustration). It is important to note that the chance of passing on a genetic condition applies equally to each pregnancy. For example, if a couple has a child with an autosomal recessive disorder, the chance of having another child with the disorder is still 25 percent (or 1 in 4). Having one child with a disorder does not “protect” future children from inheriting the condition. Conversely, having a child without the condition does not mean that future children will definitely be affected. Although the chances of inheriting a genetic condition appear straightforward, factors such as a person’s family history and the results of genetic testing can sometimes modify those chances. In addition, some people with a disease-causing mutation never develop any health problems or may experience only mild symptoms of the disorder. If a disease that runs in a family does not have a clear-cut inheritance pattern, predicting the likelihood that a person will develop the condition can be particularly difficult. Estimating the chance of developing or passing on a genetic disorder can be complex. Genetics professionals can help people understand these chances and help them make informed decisions about their health. For more information about passing on a genetic disorder in a family: The National Library of Medicine MedlinePlus web site offers information about the chance of developing a genetic disorder on the basis of its inheritance pattern. Scroll down to the section “Statistical Chances of Inheriting a Trait” for each of the following inheritance patterns: Autosomal dominant Autosomal recessive X-linked dominant X-linked recessive

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