Lecture #8

Question 1

What distinguishes X-linked dominant traits from autosomal dominant traits?

Answer 1

in x linked dominant traits males pass the traits onto all of their daughters and none of their sons

Question 2

What are some of the characteristics of Y-linked recessive traits?

Answer 2

only appears in males, passed from father to all male offspring, neither dominant nor recessive

Question 3

What is an ultrasound used for?

Answer 3

measures the thickness of the fluid buildup under the skin at the back of the baby’s neck

Question 4

What is amniocentesis?

Answer 4

when amniotic fluid is removed and tested

Question 5

What is the process of chorionic villus sampling?

Answer 5

A catheter is inserted into the uterus and is in contact with the chorion so a small piece of the chorion is removed

Question 6

What is fetal cell storing?

Answer 6

the sorting of fetal cells from maternal cells

Question 7

What individuals are at possible risk of PGD?

Answer 7

Carriers of sex-linked genetic disorders or of single gene disorders
Those with chromosomal disorders
Women age 35 and over, or experiencing recurrent pregnancy loss, or more than one failed fertility treatment

Question 8

what are the characteristics of X-linked recessive inheritance?

Answer 8

an affected male does not pass the trait to his sons, but can to his daughters, daughters can then be carriers who have affected sons, usually more males than females are affected

Question 9

What are the characteristics of X-linked dominant inheritance?

Answer 9

males pass the trait to all of their daughters and none of their sons, does not skip generations, more females than males are affected

Question 10

What is the process of amniocentesis?

Answer 10

Needle is inserted through abdominal wall into amniotic sac, amniotic fluid is withdrawn then fetal cells within fluid are cultured and tested

Question 11

When can amniocentesis be done?

Answer 11

14-18 weeks of gestation

Question 12

What conditions may amniocentesis testing present?

Answer 12

Large-scale chromosomal anomalies

Question 13

What is amniotic fluid also examined for?

Answer 13

Biochemical anomalies that indicate inborn errors of metabolism

Question 14

When can chorionic villus sampling be done?

Answer 14

10-12 weeks of gestation

Question 15

What is the differences in the results of the chorionic villus sampling vs. amniocentesis testing?

Answer 15

In CVS, cells are not cultured, biochem tests are not done, and is less accurate with a higher risk of miscarriage than amniocentesis

Question 16

How does fetal cell storing work?

Answer 16

through the use of fetal-specific surface markers and cell sorting

Question 17

How does pre-implantation genetic diagnosis work?

Answer 17

samples one or more embryonic cells at the 8 or 16 cell stage

Question 18

What are some problems with genetic testing?

Answer 18

many mutations are not yet understood, does not account for genetic defects, not all people with a mutation will get the disease, and no tests exist yet for many genetic traits