Twins and Cloning

Question 1

Dizygotic/fraternal twins

Answer 1

twins from two zygotes. Caused by two oocytes being ovulated and fertilized. No more genetically similar than other siblings. Behaviorally similar because of similar developmental environments.

Question 2

Monozygotic twins

Answer 2

twins from a single zygote. Called identical twins. Caused by embryo dividing into two. Generally occurs by blastocyst stage.

Question 3

Conjoined/Siamese twins

Answer 3

twins that are physically joined. Caused by incomplete separation of monozygotic twins.

Question 4

mirror image twins

Answer 4

twins with mirrored features. Caused by late twinning. Asymmetry is determined, then reversed at twinning event. External features (handedness) is reversed. Internal organs reversed in one twin.

Question 5

Somatic cell nuclear transfer (SCNT)

Answer 5

Clones donor of somatic cells.

Question 6

Honolulu technique

Answer 6

Remove somatic cell nucleus, Remove oocyte nucleus, add somatic cell nucleus to oocyte, promote fusion of a new nucleus and oocyte.

Question 7

Roslin Technique

Answer 7

Remove oocyte nucleus, Put cells near each other and shock them to promote fusion.

Question 8

SCNT differences between clone and original

Answer 8

Soul, X-chromosome inactivation pattern (random differences in female clone), uterine environment, mitochondrial DNA, parents

Question 9

Pronuclear Transfer

Answer 9

Clones zygote. 1 parent contributes nuclear DNA, 1 (Honolulu) or 2 (Rosin) contribute mitochondrial DNA.

Question 10

Pronuclear Transfer steps

Answer 10

Remove zygote 2 pronuclei, add zygote 1 pronuclei to zygote 2, promote fusion

Question 11

Maternal spindle transfer

Answer 11

No clone created. 1 parent contributes DNA from sperm, 1 parent contributes form oocyte 2 mitochondria, 1 parent contributes DNA from oocyte 1 nucleus = 3 parents.

Question 12

Maternal spindle transfer steps

Answer 12

remove oocyte 2 nucleus, add oocyte 1 nucleus to oocyte 2, fertilize new oocyte

Question 13

Altered Nuclear Transfer (ANT) Steps

Answer 13

Remove oocyte nucleus, alter somatic cell nucleus, add altered somatic cell nucleus to oocyte

Question 14

ANT purpose

Answer 14

prevent creation of a new organism to ethically harvest stem cells

Question 15

ANT concerns

Answer 15

may create an organism with a severe disability, research may not be ethically possible.

Question 16

Chromosome

Answer 16

an organized strand of DNA found in nucleus of the cell Humans have 23 kinds (1 set).

Question 17

Diploid

Answer 17

having two sets of chromosomes

Question 18

Tetraploid

Answer 18

having four sets of chromosomes

Question 19

Tetraploid Complementation steps

Answer 19

Fuse cells of two normal embryos, grow to blastocyst stage, inject stem cells into inner cell mass, grow embryo

Question 20

tetraploid Complementation

Answer 20

used to confirm potential of injected stem cells. If successful, the stem cells can create all cells of the body.

Question 21

Reproductive cloning

Answer 21

cloning used for reproduction, Uses SCNT

Question 22

Therapeutic cloning

Answer 22

cloning used for therapies. Doesn’t use SCNT. Clone is killed to harvest stem cells. Procedure is identical to reproductive cloning.

Question 23

Human clones

Answer 23

Created using roslin technique. Hybrid (cow oocyte + human nucleus) and Human.