What you need to know The major goals of the Human Genome Project How prokaryotic genomes compare to eukaryotic genomes Applications of bioinformatics to medicine evolution and health The activity and role of transposable elements and ID: 779023
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Slide1
Chapter
18
Genomes and Their Evolution
Slide2What you need to know:
The major goals of the Human Genome Project.
How
prokaryotic genomes compare to eukaryotic genomes
.
Applications of bioinformatics to medicine, evolution, and health.
The activity and role of transposable elements and
retrotransposons in generating genetic diversity.
How
evo-devo
relates to our understanding of the evolution of genomes.
The role of homeotic genes and
homeoboxes
in developmental patterns and sequences.
Slide3Bioinformatics
Use of computers, software, and math models to process and integrate data from sequencing projects
Proteomics
= Analyzing
protein
interactions
Genomics
:
study
whole sets of genes and their interactions
Slide4Human Genome Project
Purpose
: to sequence the entire human genome
Completed in 2003
Genomes sequenced thus far*:
129,936
prokaryotes,
5102
eukaryotes,
14,004
viruses
*
NCBI database
as of
1/23/18
Slide5Human Genome Project
Whole-genome shotgun approach
to sequencing
Slide6Comparing Genomes of Bacteria, Archaea
, & Eukaryotes
Slide7Comparing Genomes
Bacteria & Archaea have fewer genes than eukaryotesNo correlation between complexity of organism and # of genes
Slide8Human DNA
3 billion base pairs
~20,000 genes
Only
1.5%
codes for proteins (or RNA)
Mostly
Repetitive DNA
: sequences present in multiple copies
Slide9Transposable Elements
Make up 75% of repetitive DNA
Stretches of DNA that can be moved from one location to another in genome
Discovered by Barbara McClintock – corn breeding experiments
2 Types:
Transposons
Retrotransposons
Slide10Transposons
Moves within genome via DNA intermediate
“
cut & paste
”
or
“
copy & paste
”
mechanisms
Requires enzyme
transposase
Slide11Retrotransposons
Move by means of RNA intermediate
Leaves copy at original site
Involves enzyme
reverse transcriptase
Slide12Other Repetitive DNA
Short Tandem Repeat (STR)Repeating units of 2-5 nucleotides# of copies varies from site to siteRepeats vary from person to person
unique set of genetics markers
Genetic profiles
created by STR analysis
Slide13Genome Evolution
Insertion effects of
transposons
:
Can interrupt or alter gene function
Multiple copies of genes
Duplication
genes with related functions
Genes diverge by accumulating mutations
Some become nonfunctional
pseudogenes
Eventually, new genes with new functions can occur
Slide14Multigene Families
Collections of 2 or more identical or very similar genes
Eg
. hemoglobin:
-globin and
-
globin gene families
Slide15Slide16Transpositions
C
hromosomal
R
earrangements
Slide17Transposable elements contribute to evolution
Promote recombination, disrupt genes or control elements, & carry genes to new locations
May be harmful or lethal, but can also have small beneficial effects
Provides raw material for natural selection
Slide18HHMI Short Film:
The Birth & Death of Genes
Slide19Illustrative Example:
Antifreeze Gene in Fish
Antifreeze proteins (AFP):
produced by vertebrates, plants, fungi, bacteria to aid survival in sub-zero environments
Function
: bind to ice crystals and prevent growth
Antarctic fish
: old protein gene transformed into a new gene with new structure/function
Gene mutates
duplicated
divergent evolution
Evolutionary Development
(
Evo-Devo
)
Compare
developmental processes to understand how changes can lead to evolution of organisms
Slide21Video Clip:
What are SNPs?
Slide22Homeotic Genes
: master regulatory genes
Codes for transcription factors
Control
placement and spatial organization of body parts by controlling developmental fate of groups of cells
Homeobox
:
widely conserved
180-nucleotide sequence within homeotic (
Hox
) genes
Found in many groups (fungi, animals, plants) with very few differences
Hints at relatedness between all life forms
Slide23Conservation of homeotic genes