Doctor insights on:
History Of Dna Sequencing
Replication error: Most changes in dna come from errors in the duplication of the dna. But changes can occur in the structure from radiation and some chemicals especially those used in chemotherapy. Most mutations are harmless, some are tracked down by your normal reparative mechanism but a few can cause trouble including cancer. ...Read more
Which HIV tests are considered genetic?what the meaning of genetic test?is HIV DNA PCR a genetic test?and what type of test can detect all HIV types?
Luck: Mutations are usually luck based. Bad luck. Other non-genetic deformities are often genetic or environmental, but can also be bad luck too. ...Read more
What is the difference in gene sequencing tests vs gene deletion/duplication tests? Should one type of genetic test be done before the other?
Depends: Sequencing is like reading war and peace letter by letter, and deletion/duplication testing is like seeing if a chapter is completely missing or present as an extra copy. Which first? Depends on the condition. For duchenne muscular dystrophy, look for deletions first. For brca, sequence first. Your clinical geneticist can discuss the strategy with you. ...Read moreSee 1 more doctor answer
Safety of chorionic sampling vs. Amniocentesis for prenatal diagnosis of chromosomal abnormalities?
Risks: The risk of pregnancy loss has been looked at in four randomized studies of cvs vs. Amniocentesis. All four studies show that both procedures have about the same risk of pregnancy loss. About 1 in 1600. Another cvs study showed that losses in a group of women who had the procedure were equal to losses in a group of women who didn't have the procedure. A loss may not be related to the procedure. ...Read more
What are the odds of having a faulty HIV test? This includes antigen, PCR RNA tests, and antibody tests.
HIV testing...: 4th gen HIV testing and other tests are all fairly accurate. If there are concerns they can be repeated. If negative results 6 months after concerning exposure it is highly unlikely that results are inaccurate. Talk to your doctor about results if you are concerned and always remember to limit your risks with future sexual encounters: use protection, avoid high risk scenerios ...Read more
We're Getting There: In the past, we used anatomic staging alone (tumor size, lymph node involvement) to guide rx. Gene profiling allows us a completely separate measure of prognosis, and, more importantly, can predict who may or may not benefit from different chemotherapy agents. In the future, we will hopefully be able to tailor our rx to the specific cancer being treated: the elusive personalized medicine. ...Read more
Are the sex chromosomes x and y solely responsible for the appearance of any gender specific traits?
3 early MCs & chromosomal abnrml in all fetuses (no birth), is karyotyping of parents the only genetic testing tht can be done? Names of any other pls
It's the starting pt: Parent study comes first.A person can appear normal if they carry all the proper chromosome material but with part belonging to one chromosome swapped with another.(ie, part of a #15 is on #21) When fertilization occurs, the fetus may get part of the mistake and not the other & be defective.Some of these have a partial chance of normal birth, some would always end up a defect.See a geneticist. ...Read more
Vast issue: Genetic testing can help with diagnosis of tumors, indicate optimal treatment of tumors and other disease, help in prognostication, risk of development of some diseases, e.g. Colon cancer. Genetic testing is essential for counseling in inherited disorders, e.g., tay sachs disease. Genetic testing may be used for diagnosing diseases in the fetus and the list is increasing rapidly. ...Read more
Incomplete versus : In 2000, the human genome project announced an assembled working draft of the sequence of the human genome. They assembled over lapping fragments covering 97% of the human genome. The draft was much more complete than they had expected--over 22.1 billion basis of raw sequence data totaling 7-fold sequence coverage. 24% was completely finished, and 50% in near finished or better form. ...Read more
Can chromosomal microarray detect down syndrome? What's the difference between chromosomal microarray and the conventional karyotypying?
It may, depends: First step is conventional karyotyping, if the clinical suspicion present for Down syndrome, detection of an extra chromosome 21, or triploidy, instead of two. In 95% of Down syndrome it's diagnostic, but If it didn't detect and suspicion still there - next step could be a microarray, which designed to detect submicroscopic abnormalities not detected by regular karyotyping for the rest of 5% D-se ...Read more
Hemphillia: Genetic testing is also available for the factor viii gene and the factor ix gene. Genetic testing of the fviii gene finds a disease-causing mutation in up to 98 percent of individuals who have hemophilia a. Genetic testing of the fix gene finds disease-causing mutations in more than 99 percent of individuals who have hemophilia b. Genetic testing is usually used to identify women who are carriers. ...Read more
Sev. Dev. Delay -array comparative genetic hybridization (acgh) results indicate no abnormalities- would full genetic sequencing be advised (knome)?
Not necessarily: Newer genetic tests provide incite into a variety of issues like autism & other developmental variations.Yet causation remains elusive in many cases.Sadly, an injury to the developing brain centers from an unrecognized event in an otherwise normal pregnancy is a likely cause for many.This occurs in at least half of cerebral palsy cases & dev.Delay could be produced in others, yet hard to prove. ...Read more
How do dna, mutation, genotype, phenotype, and natural selection interconnect to cause evolution?
Modern synthesis: It's as well-established as anything in science, but would take more than 400 characters to explain. You owe it to yourself, as an educated person who must participate in community decision making, to understand it. There are a huge number of good books on the subject. Best wishes. ...Read more