locating genes, genetic screening and counselling

Question 1

What are DNA probes?

Answer 1

• a DNA probe is short, single-stranded length of DNA that is radioactively or flourescently labelled
• to make a probe we need to know the base sequence in the particular allele that we are trying to locate a DNA probe is made with a complementary base sequences of the up the desired allele
• recombinant DNA technology has enabled us to diagnose and treat genetic disorders but DNA probes are needed to show exactly where a particular gene is located

Question 2

What is DNA hybridisation?

Answer 2

• a section of DNA or RNA is combined with a single-stranded section of DNA which has complementary bases
• the two strands of the DNA molecule must be separated by heating the DNA to denature the hydrogen bonds
• when cooled, the complementary bases on each strand recombine with each other to reform the original double strand
• given sufficient time all strands in a mixture of DNA will pair up with their partners
• DNA fragments are just as likely to annual with one of the separated DNA strands as the DNA probe
• the site at which the probe binds can be identified by the radioactivity or fluorescence that the probes emits

Question 3

What is genetic screening?

Answer 3

• many genetic disorders come from gene mutations that can either be dominant or recessive meaning you either express the disorder or are a carrier
• genetic screening allows you to determine whether or not you are a carrier so you can be referred to a genetic counsellor

Question 4

What is personalised medicine?

Answer 4

• one of the advantages of genetic screening is personalised medicine
• it allows doctors to provide advice and health care based on an individuals genotype
• some people’s genes can mean that a particular drug ,may be either more or less effective in treating a condition
• by genetically screening patients, doctors and pharmacists can determine, more exactly, the dose of a drug which will produce the desired outcome
• this can save money that would otherwise be wasted on overprescribing the drug
• in some cases it avoids medications that could cause harm or avoids raising false hopes

Question 5

What is genetic counselling?

Answer 5

• genetic counsellors can give advice to people on how to improve their lifestyle if they have a genetic disorder
• if they are carriers of a genetic disorder they can be informed how likely they are to have children with the disorder and help them understand the psychological, emotional and medical consequences as well as how to raise a child with the disorder or suggest they get IVF