Exam 2 Terms (meant for developmental genetics) Flashcards
What stage of development is this?
Egg and sperm combine to create zygote
fertilization
What stage of development is this?
Zygote does mitosis to form blastocyst
cleavage
What stage of development is this?
Blastocyst creates germ layers
gastrulation
What stage of development is this?
Germ layers arrange themselves in to organs
organogenisis
___________ is when the egg is able to develop without the sperm
parthenogenisis
What is karyokinesis?
mitotic division of cell nucleus
Can karyokinesis occur without cytokinesis?
Yes, forms multiple nuclei in one cell
What is a holoblastic cleavage?
eggs containing no yolk is cleaved
What is a meroblastic cleavage?
eggs containing only yolk is cleaved
What are the 3 body axes?
- dorsal/ventral
- anterior/posterior
- lateral (left-right)
When does the first signs of polarity occur?
in a minute
What are the 3 germ layers?
- ectoderm
- mesoderm
- endoderm
What is the order of the germ layers?
Ectoderm (outer)
Mesoderm (middle)
Endoderm (inner)
What organs will the endoderm layer form?
gut
what organs will the mesoderm layer form?
muscles
circulatory system
blood
what organs will the ectoderm layer form?
skin and nervous system
What type of cell movement is this?
in-folding of cell sheet into the embryo
invagination
What type of cell movement is this?
in-turning of a cell sheet over the outer layer
involution
What type of cell movement is this?
migration of individual cells into the embryo
ingression
What type of cell movement is this?
splitting/migration of one cell sheet into two sheets
delamination
What type of cell movement is this?
expansion of one cell sheet over the over
epiboly
In regards to B-catenin over-expression during sea urchin development, is it located in the nuclei? and what germ layers are present?
ALL nuclei; endoderm and mesoderm
During organogenesis, which organ/system develops first?
nervous system
During development of the nervous system, ______________ grows and induces overlying ectoderm to form a neutral plate, groove, then fold
notochord
What two transcription factors are required for development of the neural tube?
TGF-B and SHH
During the development of the neural tube, is the transcription factor TGF-B on the dorsal or ventral side?
dorsal
In plant development, do apical or basal cells become shoot tissue?
apical
Can plants continue to develop post-embryonic and why?
yes; they are totipotent
What is the main plant hormone involved in polarity?
auxin
What are the three ways to measure hormone levels?
- direct measurements
- antibodies
- reporters
What is an example of measuring hormone levels using reporters?
transgenic lines (indirect)
What species has the only full fate map?
C. elegans
Why is is difficult to make full fate maps?
you have to watch every single cell division
What are 5 tools of fate mapping?
- vital dyes
- fluorescent dyes
- genetic marking
- physical cell destruction
- molecular tools
In regards to fate mapping tools, what kind of tool is mutation or RNAi analysis or transcriptomics?
molecular tool
In regards to fate mapping tools, what kind of tool is molecular marking like reporter genes?
genetic marking
What is a common type of fluorescent dye?
GFP
What is a morphogen?
any compound that influences the fate of a cell based on its concentration (how close the cell is to the morphogen)
Why are morphogens important for development?
establishes polarity
When tissue is transplanted how does it adapt to its new environment?
tissue doesn’t respecify but it does differentiate to adapt to new levels of morphogens
Morphogen gradients can drive expression BUT…?
only of genes of the same origin
What 2 things make a molecule a morphogen?
- cells respond directly to that molecule
- differentiation of the cells will depend on the concentration of that molecule (morphogen)
Why would a strip of expression form on a morphogen gradient?
some gene expression needs to be in the “just right” range
What 6 mechanisms are used to interpret or regulate a morphogen gradient?
- differential binding site affinity
- combinatorial input
- feed forward loop
- positive feedback
- cross repression
- reciprocal repressor gradient
Describe differential binding site affinity
binding sites require different [morphogen] to activate
Describe combinatorial input
requires X+morphogen to activate
Describe feed forward loop
X+Y = XY = activated
Describe positive feedback
once turned on doesn’t turn off
Describe cross repression (symmetrical and asymetrical)
symmetrical: 2 genes repress each other
asymmetrical: 1 gene represses another
Describe reciprocal repressor gradient
2 gradients oppose each other (2 triangles make a rectangle)
Gradients are not static. Why?
they are affected a lot by time
What are the 2 processes of developmental progression in flies?
- polarity formation
- formation of body segments
In what order do flies body segments develope?
- parasegments
- embryonic
- adult
What are the three major classes of genes controlling development in flies ?
- maternal effect genes
- segmentation genes
- homeotic genes
What do maternal effect genes establish in flies?
body axes
Maternal effect genes in flies are bicoid, nanos, and torso genes. What axes do each apply to?
bicoid: anterior
nanos: posterior
torso: terminal
The maternal effect gene in flies, bicoid, induces or represses hunchback?
induces
the maternal effect gene in flies, nanos, induces or represses caudal?
caudal
maternal effect gene, bicoid, forms what structure in flies?
head
In flies, what are the 3 types of segments gene in development in order?
- gap
- pair rule
- segment polarity
In flies, how are gradient boundaries maintained?
paracrine loops
In flies, what does homeotic genes form?
organs
What is the homeotic mutation, antennapedia, in flies cause?
antennae into legs
What is the homeotic mutation, ultrabithorax, in flies cause?
extra wings
Is macro or micro evolution observing changes at the species level?
micro
what is macroevolution?
large scale changes based on changes in modules
What are modules?
parts of organism that can be changed without interfering with function of other body parts
At the gene level, modules occur via ____________
molecular parsimony
What is molecular parsimony?
gene duplication followed by redifferentiation of function
What is the type of molecular parsimony, subfunctionalization, look like?
when the gene is duplicated the info is split half and half between two genes
What is the type of molecular parsimony, neofunctionalization, look like?
one copy is normal and the second has mutation
_________ is a gene related to another gene evolutionarily
homolog
_________ are related genes in different species which evolved from a common ancestor (speciation)
ortholog
_________ are related genes within the same genome, which have appeared via a gene duplication event
paralog
Do paralogs or orthologs often retain the same function over time
orthologs
Do paralogs or orthologs often evolve novel functions or non functionals
paralogs
Can signal transduction pathways be homologous?
yes
What do Homeobox (hox) genes specify?
body parts and segment identity
All homeotic genes conatin the segment gene ___________
homeobox
What are the 4 mechanisms of macroevolution?
- heterotopy
- heterochrony
- heterometry
- heterotypy
What is the macroevolution mechanism heterotopy?
change in expression location
What is the macroevolution mechanism heterochrony?
change of expression timing
What is the macroevolution mechanism heterometry?
change in expression amount
What is the macroevolution mechanism heterotypy?
change in function
What macroevolution mechanism when increased affects the coding region of the gene
heterotypy
Phenotype is the genotype + __________
enviorment
What is phenotypic plasticity?
a genotype may develop distinct phenotype in response to different environment
Plasticity is under _________ control
genetic control
what are the three ways environment alters phenotype?
- direct activation of signaling pathways
- modification of genes
- indirect activation
What are 2 examples of direct activation of signaling pathways because of environment?
pressure/gravity
light
What is an example of modification of at the gene level because of the environment?
mutations/allele formation
does calories restriction increase life span and how?
increase life span through lower metabolism
In grasshoppers, when populations are high what do the adults look like?
brown, long wings, migrate
What chemical is DDT?
insecticide
what chemical is dioxin?
by-product of pesticides and paper plants
what chemicals are PCPs?
used in refrigerants
What are endocrine disruptors?
drugs/chemicals that mimic or interfere with hormones
What is an example of an endocrine disruptor?
DES
What are environmental estrogens?
class of chemicals that mimic estrogen
what chemical is BPA?
in plastics; synthetic estrogen
