2.11 Developmental Genetics

Question 1

What are totipotent cells?

Answer 1

Ability of a single cell to divide and produce all of the differentiated cells in an organism

Question 2

What are pluripotent cells?

Answer 2

Ability of a single cell to divide and produce SOME but not all kinds of differentiated cells in an organism

Question 3

What are unipotent cells?

Answer 3

Ability of a single cell to divide and produce a single kind of a differentiated cell in an organism.

Question 4

What are the steps used in cloning a mammal?

Answer 4

Extract a cell from a sheep. Remove nucleus from fertilized egg. Replace that with the nucleus of this cell (that was extracted from this full grown sheep). Gave it an electric shock (recreating signals that happen right after fertilization), the egg activated and divided. Thus turns into like IVF, implant into a fertile sheep, and it grew.

Question 5

How is egg polarity established?

Answer 5

By egg-polarity genes and Polarity is determined by where the concentration gradients are.

Question 6

What is the homeobox? How is it different from the homeodomain?

Answer 6

Genes that contain a highly conserved seq of nucleotides, which codes for the 60 AA homeodomain found in homeodomain transcription factor proteins.

Question 7

What role do homeobox-containing genes play in vertebrate development?

Answer 7

Play a major role to cranio-caudal segmentation, in main body axis and within development of many organs.

Question 8

Compare loss-of-function mutations to gain-of-function mutations

Answer 8

Loss of function mutations result in posterior to anterior transformations while the gain mutations result in anterior to posterior transformations

Question 9

What is the organization of the human HOX complex?

Answer 9

Humans have 4 clusters of HOX genes.

Question 10

Compare the HOX gene complex in mammals to that in Drosphila

Answer 10

HOX genes are in 4 clusters in mammals vs 1 in drosphilia. However both mammal and drosphilia HOX genes are similar in sequence, and they are in the same order.

Question 11

What is somatic cell nuclear transfer?

Answer 11

laboratory strategy for creating a viable embryo from a body cell and an egg cell.

Question 12

What is heterotaxy?

Answer 12

Lack of differentiation of R-sided and L-sided organs during fetal development

Question 13

What genes establish the main body axes?

Answer 13

Egg-polarity genes

Question 14

What genes determine the number and polarity of body segments?

Answer 14

Segmentation genes

Question 15

What genes establish identity of each segment?

Answer 15

Homeotic genes

Question 16

Pertaining to egg-polarity genes what do the maternal origin do?

Answer 16

Determine anterior-posterior and dorsal-ventral axes of the embryo are initiated by mRNA from the mom.

Question 17

What is morphogen?

Answer 17

a protein that affects the developmental fate of the surrounding region through a concentration gradient

Question 18

What gene determines the dorsal-ventral axis?

Answer 18

Dorsal gene

Question 19

What genes determine the anterior-posterior axis?

Answer 19

Bicoid gene, nanos gene, hunchback gene

Question 20

What genes determine the anterior-posterior axis?

Answer 20

Bicoid gene, nanos gene, hunchback gene

Question 21

In what direction are homeobox-containing genes activated?

Answer 21

3’ to 5’ direction

Question 22

What are hox genes?

Answer 22

Encode transcription factors that help determine the identity of body regions

Question 23

What are hox genes?

Answer 23

Encode transcription factors that help determine the identity of body regions

Question 24

What is apoptosis?

Answer 24

Controlled, programmed cell death

Question 25

What is necrosis?

Answer 25

Injured cells dying in an uncontrolled manner

Question 26

Precise regulation of gene expression is essential for what?

Answer 26

Development

Question 27

Darwins observation of finches different peaks was due to what?

Answer 27

Natural selection leads to environmental specialization. Peak difference was due to changes in expression levels of calmodulin

Question 28

Mutations in homeotic genes often causes what?

Answer 28

Structures to appear in wrong places