final bio part I

Life begins with…

Life begins with…

a complete genome

Human genome project (1990-2003)

Determined complete nucletide sequence of each chromosome

complete nucleotide sequence

Chimpanzee

Corn

E. coli

Fruit fly

Bovine

Mg

megabase=millon base pairs

Genome

the entire set of DNA from an organism

Gene density

number of found along a Mb stretch of DNA

Eukaryotes have larger genomes than prokaryotes

Eukaryotes have more genes than prokaryotes

Within eukaryotes

-no systematic relationship b/w genome size & phenotype

-no crrelation between number of genes and genome size

Humans genes and genome

50k-100k predicted

3000 Mb genome (3Gb)

large multicellular eukaryotes genomes have

lower gene density

Have lowest gene density

humans and other mammals

genome for humans

15 genes/Mb in 3000 Mb genome for humans

genome for C- elegans

200 genes/ Mb in 100 Mb genome for C. elegans

Due alternative splicing of RNA transcripts

Eukaryotes can produce more than one protein per gene

The BEST at alternative splicing

VERTEBRATES

exons

1.5% encoding regions for proteins, rRNA, tRNA

regulatory sequences

5%

introns-non coding elements

20%

makes our genes larger

intergenetic repetitive DNA

45% makes our GENOME larger

transposable genetic element

75%

large segment duplications

6%

make our GENOME larger

44% of human genome

intergenitc (between genes) repetitive DNA

75% of intergentic repetitive DNA is made of

transposable elements

transposons

retrrotraposons

how do genetic modifications occur?

Rearrangement of genes

Duplication of genes

Mutuation of genes

2 types of mobile genetic elements

are common mechanism of genetic modification

Barbara McClintock

corn

Transposons

mobile genetic elements

DNA can be moved around the genome by 2 methods

Leaves a copy of DNA at original site

Copy & paste

No copy of DNA left at original site

Cut & Paste

Transpons happend via transponsase encoded in transposon region

DNA to DNA movement

Most common mobile genetic elements

Retrotransposons

Retrotransposons

RNA intermediate is key

Rerverse transcriptase is encoded in retrotransposons

Retransposons

New copy is inserted in novel location in genome

Retrotransposons

Original copy remains

Copy and paste method through RNA intermediate

Retrotrransposons

Plants with very large genomes, more transposable elements; NOT genes

Barbara Mcclintock

We would not know BArbara

if Barbara studied rice

Nobody believed her until the same thing was described in bacteria

descent with modification

Evolution

Many species were descedants of ancestral species very different from those alive today

Darwin proposed

Changes in genetic composition of a population over time

Evolution

Scala Naturae

Ladder of creation

Perfect & permanent

NO evolution

Aristotle

Father of Taxonomy

Linnaean Taxonomy

Binominal nomenclature

Genus species

NO evolution

Species divinely created

Perfect & PERMANENT

“nested classification”

Carl von Linne

Carolus Linnaeus

know for his mistake!

Evolutionary Theory

Driven by NEED

Mechanismo= Inherit ACQUIRED characteristics

De Lammarck

ACCQUIRED TRAIT

the change is not written in the genome

HERITABLE TRAITS

traits carried in the genome heritable traits can be passed on to future generations

Father Paleontology = study fossils

Cuvier

Examined strata (layers of sedimentary rock)

Observed older fossils=more dissimilar form modern

Cuvier

Established extinctions as a phenomena

Cuvier

Catastrophism as mechanism of evolution

(floods, draught)

Only way to evolve is through disaster/ disturbance

Cuvier

2 Important influences on Darwin

James Hutton

Charles Lyell

Theory of Gradualism

Profund geologic changes were cumulative

slow and continous process

James Hutton

Geologist

Theory of UNIFORMITARIANISM

geologic processes had not changed throught Earth´s history

Charles Lyell

Corn genome has 85%

transposable elements

Based on Hutton and Lyell´s theories, Darwin surmised…

If geologic changes are the result of slow, continuous change, Earth is older than theologians infer.

Slow, subtle, processes presisting for long periods could also act on organism, producing, substantial changes over time.

Father of biogeography

sent Darwin his theory

share credit for similar theories

Darwin was more complete

Natural Selection as mechanism of evolution

A. R. Wallace

Was introudced as mechanism of evolution

Natural Selection

Mechanism of evolution

Natural Selection

Process in which individuals have certain heritable traits survive and reproduce at higher rate than other individuals becuase of those traits.

Natural selection

Increase the match between organisms and their environment

natural selection over time

enviroment changes

individuals move to a new environment.

will result in adaptation to these new conditions, sometime giving rise to new species in the process

natural selection

Individuals do NOT evolve,

POPULATIONS do. A population is the smallest group that can evolve over time

Can act only on heritable traits

natural selction

is favorable in one environment may be useless or even detrimential in another environment

A trait

Organism no longer match

because of climate change: BAD

Supported by an overwhelming amount of scientific evidence

EVOLUTION

4 documentation of evolution

1. Direct observation of naturla selection

2. Fossil Record

3. Homology

4. Biogeography

Soapberry bug beak length

Based on foof they consume

Direct observation

Editing mechanism

Selects favorable traits

Natural selection

Traits adapative in one environmetn may be detrimental in another

Natural selection

Similarity in characteristic traits from common ancestry

(mammalian forelimb skeletal structure)

Homology

Similarity in chatacteristic traits from common ancestry

May only found during DEVELOPMENT

4 key CHORDATA characteristics:

post-anal tail

pharyngeal archeas

norchord

Dorsal hollow nerve cord

Trace limb structure

Trace skull bones

Fossil Record

The study of the geographic distribution of species

Camelids: continental drift is mechanism

Biogeography

Individuals do not evolve

Populations do

Favored larged break size present in individuals

Natural selection

each finch started and ended drought with original beak size

average beak size of finch population increase

natural selection favored larger beak size present in individuals

smaller beaked finches died;

larged beaked finches lived

individual finches

didn´t evolve

a change in allele frequencies in a population overtime

microevolution

Natural selection

Genetic Drift (change mutation events)

Gene flow (transfer of individual into/out of population

3 mechanism causes microevolution to happen

only mechanism of ADAPTIVE evolution

natural selection

it improve the match between organism and environment

Evolution is possible

because of genetic variation

differences among individuals in DNA composition

Usually revealed as a phenotypic variation

Genetic variation

new genes and new alleles originate…

only by MUTATION

genetic code for protein

gene

location of gene on chromosome

locus

same gene/ different sequences

alleles

1 from each parent

homologoues chromosomes

same

same size

same shape

carry same genes for same traits

homologous chromosomes

different alleles

diferent sequence for gene

Homologous chromosomes

Ocurrs during crossovers, forms new allele combinations

Sister chromatids no longer identical

recombination

Gametes with new gene combinations are produced

Recombination

genetic variation via meiosis

Genetic variation that evolution depends on has various origins

mutation

gene duplication

sexual reproduction

ultimate source of new alleles

mutation

can cause change in the nucleotide sequence of organism´s DNA

mutation

change of a single base in gene= sicle cell disease

point mutations

can alter gene number or position (locus)

can be detrimential

can be harmless

mutation