Lect. 7 - Cleavage II

Question 1

genomic imprinting

Answer 1

differential gene expression depending on whether a chromosome is inherited from the male or female parent. Refers to the observation that expression of certain genes derived from the egg differs form the same genes derived from sperm

Question 2

methylation and imprinting relationship

Answer 2

additon of methyl groups to a DNA molecule can inactivate the entire or parts of specific genes

Question 3

Prader Willi syndrome

Answer 3

small hands and feet/short statures etc. Mutation always inherited from FATHER - (deletion in long arm of chromosome 15)

Question 4

Angelman Syndrome

Answer 4

laughter/uncontrolled muscle movement; Mutation is always inherited from MOTHER - (deletion in long arm of chromosome 15)``

Question 5

What is the purpose of X inactivation?

Answer 5

dosage compensation, or preservation of the cells form an exess of X chromosomal gene products

Question 6

What brings about X inactivation

Answer 6

the action of Xist

Question 7

Xist

Answer 7

located on X chromosome; produces an RNA molecule that coats the X chromosome and induces X inactivation

Question 8

Barr bodies

Answer 8

inactive X chromosome that should have been inactivated

Question 9

regulation

Answer 9

ability of an embryo to compensate for removal of structures or for addition of structures

Question 10

dizygotic

Answer 10

twins from 2 fertilized eggs

Question 11

monozygotic

Answer 11

twins from 1 fertilized egg

Question 12

cephalopagus

Answer 12

head to head fusion

Question 13

pyppagus

Answer 13

rump to rump fusion

Question 14

cephalothoracopagus

Answer 14

fusion involving head and thorax

Question 15

thoracopagus

Answer 15

chest to chest fusion

Question 16

bateson’s rule

Answer 16

mirror image