What happens during gastrulation in a frog embryo?
embryo forms endoderm, mesoderm, and outer layers
Purpose of a fate map of an embryo
it shows where future body parts will develop from specific portions of the embryo
What does the geography analogy and mapping of the embryo tell us about development?
Parts of bodies all have specific places from which they will develop from the embryo. It is analogous to a map and latitude and longitude
In general, what is being depicted in Plates associated with chapter 4?
They are outlines with tool kit gens of where different body parts will develop
How do the tool kit genes relate to the geogrpahy analogy?
They form stripes equivalent to those of longitude and latitude
how do Hox genes relate to brain development in vertebrates?
Hox gene expression marks out where different parts of the hind brain will be (as marked out by rhombomeres) Howx genes are expressed in the rhombomeres
They are the building blocks of vertebrate bodies and are often found in repeating structures (ribs, vertebral column, muscle groups)
How do Hox genes control somite development?
They turn on starting with western boundaries and then move east
How do Hox genes control limb formation in vertebrates?
They turn on and off in a proximal to distal order to form limbs
How is programmed cell death involved in limb formation/
The tissue between digits is programmed to die so that just the digits are left
How does lateral inhibition influence animal form?
It spaces individual strucutres to create a larger piece (like feathers or hair)
What is the 'dark matter' of the genome
The part of DNA whose function cannot be determined from the sequence
In general, what does a genetic switch do?
It controls tool kit gene expression which form bodies.
They turn genes on and off
How do activators and repressors interact to control gene expression?
Repressors cancel out activators and the gene is turned off
How do multiple genetic switches interact to ontrol the location of gene expression?
Multiple genetic switches are turned either on or off. When this information is combined, it causes the gene to only be expressed at sepcific locations. It works almost like a gps.
How does adding more switches to one gene increase the flexibility of gene expression?
Adding activators increases gene expression
Removing repressors increases gene expression
Adding repressors removes some gene expression
What is the BMP5 gene and how does one gene lead to different structures in different locations of the mouse embryo?
It promotes cartilage and bone formation. It leads to different structures in different locations by having switches turned on and off at various points in development
How does one gene, the Ubx gene, control the development of the shurnken hindwing in flies?
It acts on different switches to control development of hindwings.