Exam 2: Developmental Genetics Flashcards

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1
Q

human development refers to

A

the biological and psychological development of a human being throughout their lifespan

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2
Q

t/f: slight changes in regulatory components have significant changes on development

A

true

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3
Q

define developmental genetics

A

study of the regulatory processes that control cell growth, differentiation and morphogenesis, which is the process that gives rise to tissues, organs, and anatomy. it is the study of cell fate, cell determination and differentiation and pattern formation

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4
Q

define determination

A

process by which a cell or part of an embryo becomes restricted to a given developmental pathway

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5
Q

define differentiation

A

process by which a cell becomes dedicated to perform a specific function (ex liver, blood cell, neuron) takes during development that determines which genes are expressed and hence what type of cell will result

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6
Q

totipotency

A

ability of a single cell to divide and produce ALL of the differentiated cells in an organism (~32 trillion)

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7
Q

pluripotent

A

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

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8
Q

unipotent

A

ability of a single cell to divide and produce a SINGLE KIND OF DIFFERENTIATED CELL IN AN ORGANISM

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9
Q

alterations to key regulatory sequences often bring about

A

major developmental changes

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10
Q

pluripotent, embryonic stem cells originate as _ these stem cells can become an tissue in the body, excluding _

A

inner mass cells w/in a blastocyst; excluding a placenta

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11
Q

only the morula’s cells are _, able to become all tissues and a placenta

A

totipotent (16 cells)

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12
Q

hematopoietic stem cells are an example of _

A

multipotency; when the differentiate into myeloid or lymphoid progenitor cells, they lose potency and become oligopotent cells with the ability to give rise to only the cells of its lineage

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13
Q

many kinds of plants can be cloned from isolated single cells. thus _

A

none of the original genetic regulatory potential is lost during development

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14
Q

in order to clone an animal, _ must be reestablished

A

totipotency

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15
Q

describe how to clone an animal

A
  • remove nucleus of donor cell and replaced w/ the nucleus from somatic cell
  • give right environmental conditions to lead to development of organism (fertilization and meiotic events)
  • replaced in uterus of a pseudo pregnant female animal
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16
Q

why is establishing polarity important

A

determines what goes where; once you know the poles you can begin segmentation ie pattern formation (where structure form) and going to have a unique set of genes at each pole

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17
Q

axes are important for

A

reference points; dorsal-ventral and anterior-posterior axis and this is how polarity is established

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18
Q

after axes are established, what happens next?

A

the number and orientation of the body segments are determined and the identity of each indiv segment is established

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19
Q

_ controls each of these 3 stages: axes, polarity, segmentation

A

different sets of genes

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20
Q

the developing embryo must have mechanisms to measure _ and _ in order to complete the developmental process w/ precision

A

time and location

21
Q

in fruit flies, what genes are for developmental stage establishment of main body axes

A

egg-polarity genes

22
Q

in fruit flies, what genes are for developmental stage determination of number and polarity of body segments

A

segmentation genes; genes get affected together in the right space and time because contain similar promoters

23
Q

in fruit flies, what genes are for developmental stage establishment of identity of each segment

A

homeotic genes

24
Q

egg-polarity genes have a _ origin

A

maternal origin; determination of anterior-posterior and dorsal-ventral axes of the embryo are initiated by mRNA from the mother

25
Q

define morphogen

A

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

26
Q

cell fate is a consequence of

A

saturation/concentration; dosage is important for genes and ratios need to be appropriately maintained as genes are dosage sensitive

27
Q

_ gene in determination of the dorsal-ventral axis

A

dorsal gene

28
Q

_ gene in determination of the anterior-posterior axis

A

bicoid gene, nanos gene, hunchback gene

29
Q

gap genes are for

A

the body plan (affect large sections of the embryo)

30
Q

homeotic genes in drosophilia

A

identity of segments

31
Q

homeobox genes in other organisms

A

genes encoding DNA binding proteins; these proteins usually play a regulatory role (control development of segments/segmentation)

32
Q

Hox genes

A

encode transcription factors (TFs) that help determine the identity of body regions

33
Q

consequence if homeobox genes are expressed inappropriately

A

lead to inappropriate development of appendages/phenotypes in the wrong place

34
Q

homeotic genes are expressed

A

sequentially; the arrangement of the genes on the chromosome corresponds to the sequence in which the genes are expressed along anterior-posterior axis of the body (fruit flies)

35
Q

Hox genes are defined as having the following properties: (3)

A
  1. their protein product is a TF
  2. contain a DNA seq aka the homeobox (180 bp encodes a protein domain aka homeodomain which can bind DNA)
  3. organization of the Hox genes of the chromosome is physically the same as the order of their expression along the ant-post axis of developing animal
36
Q

definition of homeobox-containing genes

A

genes that contain a highly conserved seq of 180 nucleotides called the homeobox which codes the 60 aa homeodomain found in homeodomain TF proteins

37
Q

homeobox-containing genes characteristics (4)

A
  1. play a major role in vertebrates w/ regard to cranio-caudal segmentation, not only along main body axis but w/in the development of many organs
  2. activated in 3’-5’ direction (opp of transcription)
  3. loss of fcn mutations
  4. gain of fcn mutations
38
Q

loss of fcn mutations in homeobox-containing genes

A

result in posterior to anterior transformations

39
Q

gain of fcn mutations in homeobox-containing gens

A

result in anterior to posterior transformations

40
Q

a _ of gene regulation establishes the polarity and identity of indiv segments of drosophila

A

cascade

41
Q

humans have Hox genes in _ and Hox genes in mammals are _ to those found in drosophila

A

humans have Hox genes in 4 clusters and hox genes in mammals are similar to those found in drosophila

42
Q

heterotaxy syndrome

A

aka atrial isomerism; lack of differentiation of right-sided and left-sided organs during fetal development. organs that are normally asymmetrically paired, w/ heterotaxy have a tendency to have symmetry (2 right lungs)

43
Q

apoptosis

A

controlled, programmed cell death (orderly, signal received and DNA is cut in a specific and predictable manner, cell shrinks and is phagocytized)

44
Q

necrosis

A

injured cells dying in an uncontrolled manner (cell swells and body is responsible to clean up lysis mess)

45
Q

apoptosis in development/evolution

A

simplest and most energetically favorable way to induce change so organism can live in an environment and reproduce example is fish that has genes involved in eye development are overexpressed which led to apoptosis of the developing lens cells and lens degenerates as live in caves

46
Q

t/f: precise regulation of gene expression is essential for development

A

true; inappropriate expression of the eyeless gene causes the development of an eye of the leg of a fruit fly

47
Q

natural selection leads to environmental _ caused primarily by _

A

leads to environmental specialization caused primarily by changing expression levels of CALMODULIN which regulates the expression of many other developmental genes

48
Q

a comparison of the chimpanzee genome to the human genome showed that the sequence differs by only 1.2% in terms of single-nucleotide changes to the genetic code. how can there be such a great physical difference?

A

there are a couple of thousand nucleotide differences in regulatory regions and thus contribute to subtle changes in developmental patterns that have significant role in the evolution of the human lineage

49
Q

mutations in homeotic genes often cause:

A

structures to appear in the wrong places