LECTURE 7 - DEVELOPMENTAL GENETICS

Question 1

DEVELOPMENTAL GENETICS

• the study of the relationships between _____ ____ & _____ _____ during development

Answer 1

• gene regulation
• cell differentiation

Question 2

DEVELOPMENT

• process of regulated _____ that results from the interaction of the _____
  between _____ (2)?

Answer 2

• growth
• genome
• cytoplasm
• environment

Question 3

DEVELOPMENT INVOLVES….. (2)?

Answer 3

1. irreversible programmed sequence of phenotypic events
2. differentiation (formation of different cell types, tissues, and organs)

Question 4

different cell type are formed in development through_____ (2)?

+ under what specific process is this in development?

Answer 4

1. determination (1st step)
2. differentiation (2nd step)

EMBYROGENESIS

Question 5

PROCESS of development of a ZYGOTE? (3)

Answer 5

Single-celled zygote ->

Embryogenesis (active cell division & formation of different cell types) ->

Growth & Development ->

Complex Multicellular Organisms

Question 6

FORMATION OF DIFF CELL TYPES

Determination
- refers to when ______?
- factors that affect this?

Answer 6

• when a cell makes an irreversible commitment to follow a certain developmental path

*like when a cell determines that it would follow thru development to become an EYE CELL

DETERMINANTS

Question 7

FORMATION OF DIFF CELL TYPES

Determination - Determinants

• type of substance?
• effect on cell?

Answer 7

• cytoplasmic effector substances
• cause cells to become irreversibly committed to perform a specialized function

Question 8

FORMATION OF DIFF CELL TYPES

Differentiation
- occurs through ___?
- refers to the ______ of cell’s ______ roles

Answer 8

• specific regulation of gene expression
• expression
• specialized roles

Question 9

how do cells become specialized?

Answer 9

when they produce SPECIALIZED PROTEINS derived from LUXURY GENES

Question 10

LUXURY GENES

• genes products that are??

2 examples?

Answer 10

• not needed for survival

immature RBC = hemoglobin
beta cells of pancreas = insulin

Question 11

central question in development genetics?

Answer 11

“how does one cellular genotype give rise to many different cellular phenotypes?”

Question 12

INITIAL CYTOPLASMIC ENVIRONMENT

*talks about the initial environment of the cytoplasm

• set by the ???
• triggers the ??
• the gene products will occupy a _____ _____ in the _____ cell

*effect of cell division on cytoplasmic environment

Answer 12

• maternal genome
• triggers the switching “on and off” of genes
• specific position
• egg

*the cytoplasmic environment of each cell will be different from each other = causes formation of difference cellular phenotypes

Question 13

FORMATION OF DIFFERENT CELLULAR PHENOTYPES

• due to?
• triggers what?

Answer 13

• unequal distribution of cytoplasmic environment
• differential gene action

Question 14

IMPORTANT THINGS TO REMEMBER (2)?

Answer 14

1. differential gene function is an INTRINSIC & FUNDAMENTAL aspect of cell differentiation

*meaning lng na gene function is needed for cell differentiation to occur

2. cell phenotype is a consequence of differential gene action or selective expression of its genes

Question 15

POINTS OF CONTROL OF EUKARYOTIC GENE EXPRESSION (4)

Answer 15

1. Pre-transcriptional
2. Transcriptional Control
3. Translational Control
4. Post-translational Control

Question 16

POINTS OF CONTROL

there is SELECTIVE DNA REPLICATION

+ covers what?

Answer 16

pre-transcriptional

gene amplification amphibian oocyte rDNA

Question 17

POINTS OF CONTROL

condensation and decondensation of chromatin

+ 2 types
+ cover what process?

Answer 17

pre-transcriptional

1. loosely packed (active transcription)
2. tightly packed (inactive transcription)

DNA methylation
- a biological process by which methyl groups are added to the DNA molecule

Question 18

what do u call active chromatin

Answer 18

euchromatin (decondensed)

Question 19

what do u call inactive chromatin

Answer 19

heterochromatin (condensed)

Question 20

what is the direct effect of DNA methylation on chromatin and genes?

Answer 20

leads to
- chromatin tight packing
- gene silencing (makes it less accessible to transcription)

Question 21

POINTS OF CONTROL

differential rna synthesis

+ example
+ contains high amount of??? + where?

Answer 21

Transcriptional Control

*Xenopus Laevis

• high rRNA synthesis in immature oocytes (need high amount of ribosomes)

Question 22

rRNA synthesis is ____ during MEIOSIS or _____ _____

+ when does it resume?

Answer 22

• 0
• after fertilization
• gastrulation

Question 23

POINTS OF CONTROL

differential initiation

Answer 23

Transcriptional Control

*can use different TATA boxes to initiate transcription which can shorten ( (TATA box nearer to gene) or lengthen (TATA box farther from gene) the RNA product

Question 24

POINTS OF CONTROL

differential polyadenylation

Answer 24

Transcriptional Control

*can use a different Poly A site to terminate transcription which can shorten ( (Poly A nearer to TATA) or lengthen (Poly A farther from TATA) the RNA product

Question 25

POINTS OF CONTROL determine what point of control is being defined --- differential RNA processing

Answer 25

Transcriptional Control *differential splicing (choosing exons to retain) of RNA

Question 26

POINTS OF CONTROL determine what point of control is being defined --- selective pre-mRNA degradation

Answer 26

Transcriptional Control *selects which pre-mRNA are not needed (degraded) and needed (retained)

Question 27

POINTS OF CONTROL determine what point of control is being defined --- selective translation + example animal + when does 0 translation, low translation, and high translation occur?

Answer 27

Translational Control SEA URCHINS - 0 translation at or before fertilization - high protein synthesis after fertilization - low protein synthesis during gastrulation

Question 28

POINTS OF CONTROL determine what point of control is being defined --- stability of mRNA + covers (2)

Answer 28

Translational Control - half life of mRNA - auto-regulation

Question 29

half life of mRNA is dependent on?

Answer 29

lenght of poly A tail longer tail = longer life

Question 30

POINTS OF CONTROL determine what point of control is being defined --- modification of protein + 2 types?

Answer 30

Post-translational Control 1. Deletion of a part of a polypeptide 2. Change in the state of oxidation and reduction (malate dehydrogenase)

Question 31

POINTS OF CONTROL determine what point of control is being defined --- attachment of small residue + example

Answer 31

Post-translational Control - sialic acid attachment to phosphatase

Question 32

POINTS OF CONTROL determine what point of control is being defined --- polymerization

Answer 32

Post-translational Control *association of more than one polypeptide to produce a more functional protein

Question 33

TYPES OF NUCLEO-CYTOPLASMIC INTERACTIONS

Answer 33

1. Molecular exchanges between the nucleus and cytoplasm (amoeba) 2. Control of macromolecular synthesis in the nucleus by the cytoplasm (frog)

Question 34

on what organism was the exchange between molecules in nucleus and cytoplasm done? + explain the experiment

Answer 34

Amoeba *radioactive nucleus was inserted in an amoeba cell (so it has 1 normal nucleus + 1 radioactive nucleus) -> results show that the radioactivity spread to the cytoplasm

Question 35

GENE EFFECT ON MORPHOGENESIS "one ____ triggers the development of another ____ " + examples (2)?

Answer 35

organ organ 1. ureter arises from mesonephric bud 2. kidney arises from ureter *sd sd - normal development *Sd Sd - no mesonephruc, ureter, and kidney *Sd sd - only 1 of 2 mesonephric buds elongated and triggered the development of the ureter and kidney THUS,,, the presence of Sd gene prevents normal elongation of mesonephric bud = no ureter = no kidney

Question 36

GENE EFFECT ON ENDOCRINE SYSTEM - example?

Answer 36

mutant mice stops growing at a certain point and does not reach maturity

Question 37

why do mutant mice stop growing? (the very cause in the endocrine system?)

Answer 37

due to absence of large cells in the anterior pituitary gland

Question 38

GENE EFFECT ON GROWTH - example?

Answer 38

"creeper" trait in fowl - smaller eyes - no eyelids - misshaped head - smaller body

Question 39

do genes affect migrating cells to other regions?

Answer 39

yes causes consequences in phenotypes *migration of RBC *migration of germ cells

Question 40

what human body parts starts growing first and fastest BUT stops during adolescence?

Answer 40

Nose

Question 41

___ to ____% of DNA of chimps and humans are identical thus, this proves that?

Answer 41

98-99% "genes alone dont dictate the differences"