[Part 4]- B12- reproduction 🧬

Question 1

What is a pedigree ?

Answer 1

• a pedigree, is a family tree that shows how genetic disorders are passed down the family.
• [; this only shows phenotypes]

Question 2

Using a family tree, give one piece of evidence cystic fibrosis is caused by a recessive allele

Answer 2

• person X [11] has cystic fibrosis; neither of their parents [7 and 8] have cystic fibrosis.
• this means person X’s parents [7 and 8] must be carriers and the cystic fibrosis allele must be recessive

Question 3

What are the two main methods of embryo screening ?

Answer 3

• amniocentesis- between fifteen to sixteen weeks of pregnancy, and this involves taking some of the fluid from around the developing foetus.
• and, chorionic villus sampling- between ten to twelve weeks of pregnancy, a small sample of cells is taken from the developing placenta

Question 4

What is amniocentesis ?

Answer 4

• amniocentesis, is a method of embryo screening taken between fifteen to sixteen weeks of pregnancy, which involves taking some of the fluid from around the developing placenta

Question 5

What is chorionic villus sampling ?

Answer 5

• chorionic villus sampling, is a method of embryo screening taken between ten to twelve weeks of pregnancy, which involves taking a small sample of cells from around the developing placenta

Question 6

How is miscarriage, an issue of embryo screening ?

Answer 6

• the process used to collect cells for embryo screening, increases the risk of miscarriage.
• this means, a healthy foetus may be miscarried as a result of a test, to see whether it has a genetic abnormality [this is very distressing for parents]

Question 7

How is a false result, an issue of embryo screening ?

Answer 7

• embryo screening is becoming more reliable and accurate; there is a risk of a false positive or negative given from the results.
• this means, this could lead to the termination of a healthy pregnancy, or the unexpected birth of a child with a genetic disorder