Higher bio - evolution, selection, speciation, genomic sequencing, phylogenics, three domains of life, personal genomics

Evolution

Changes in organisms over generations as a result of genomic variation

Natural Selection

Non-random increase in the frequency of DNA sequences that increase survival and a non random decrease in the frequency of deletiourus sequences. This happens since the genetic sequences that confer an advantage are more likely to survive and reproduce and pass on the genetic sequence hence increasing the frequency of the sequence

Types of changes of phenotype frequency

Stabilising, directional, disruptive

Stabilising selection

Gets narrow with the average, favours selects average and extremes are selected against hence reduction in variation

directional selection

Graph shifts to one end, one extreme of the phenotype is selected for

disruptive selection

Two waves, two or more phenotypes are favoured

Prokaryote natural selection

They do horizontal gene transfer, more rapid hence faster evolution

horizontal gene transfer

transfer of genes between cells of the same generation, cells join together then seperate with the same gene sequence, fast evolution, no guarantee the genetic sequence gained will be beneficial

vertical gene transfer

transfer of genes from an organism to its offspring as a result of asexual or sexual reproduction

Species

a group of similar organisms that can interbreed and produce fertile offspring

Speciation

Generation of new biological species by evolution as a result of isolation, mutation and selection

Speciation explaines

Isolation barriers prevent gene flow by preventing reproduction, mutations occur in two separate groups, different mutations are selected in the groups due to different selection pressures and natural selection causes an increase in the frequency of Dna sequences that increase survival

allopatric speciation

Gene flow is prevented due to a geographical barrier

sympatric speciation

Due to behavioural or ecological barriers. When an alternate niche becomes available so some members exploit it and due to behaviour two groups no longer interbreed. Mutations occur in two groups and natural selection occurs.

Ecological

Preference

Genomic sequencing

the sequence of nucleotide bases can be determined for individual genes and entire genomes

Bioinformatics

use of computer databases to organize and statistical analyzes biological data

What is bioinformatics used for

• comparing DNA sequences

• predicting amino acid sequences

• deducing evolutionary relationships between genes Personalised medicine

Which genomes have been sequenced?

Disease causing organisms, pests, model organisms

Comparison of genes reveals

that many genes are highly conserved across different organisms, conserved genes share the same or similar nucleotide sequence across different species

Genomic sequence overlap

Genome is cut up into fragments using restriction endonuclease. Computer analyses all of it and the areas that overlap to compile a complete genome

Why are genomes Comprared

Compare organisms with disease causing organisms to see if the have important genetic sequences in common, to discover which genetic sequences or mutation causes illness,

What is phylogenetics

the study of evolutionary relationships among species

Molecular clock

Nucleotide sequence and differences are measures of how long ago they shared an ancestor

What are molecular clocks used for

...show when a species diverged during evolution. they assume a constant mutation rate and show differences in DNA or amino acid sequences. Therefore, the differences in sequence data between species indicate the time of divergence from a common ancestor

How can you tell if a species is more recently related

If they've shared a common ancestor more recently

What are the three domains?

Bacteria, Archaea, Eukarya

Main sequences of events in evolution of life

CLPPEMAVL. Cells, last universal ancestor, prokaryotes, photosynthetic organisms, eukaryotes, multicellularity, animals, vertebrates, land plants

personal genomics

The analysis and sequencing of the genome of an individual to better understand his or her ancestry or the phenotypic traits such as his or her risk of developing a disease

Pharmacogenetics

The use of genome information in the choice of drugs, the personal genome sequence can be used to select the most effective drugs

pros of pharmacogenomics

Helps target treatment towards particular mutation, indicates if someone is prone to a reaction of a drug, receive treatment early, leads to more accurate diagnosis, informs relatives if they have disorder

Cons of Pharmacogenomics

Some people don't understand, some conditions not actionable so no point, genetic discrimination, how do we disclose data