Please enable JavaScript.

Coggle requires JavaScript to display documents.

T3 Genetics - Coggle Diagram

- - - - the genome of a specifies is not a good indicator of complexity
        
        found by identifying common sequences (expressed sequence tags, presence of transposons and pseudogenes(non-functioning DNA) make this hard)
        
        for example, humans have 46 chromosomes, around 3 billion b.p and 21,000 genes and only 1.5% of those are coding sequences
      - human genome project: an innitiative to sequence the human genome, completed in 2003, led to 4 main things:
        
        Mapping - know where all the chromosomes and its gene loci are
        
        Ancestry: figure out evolution
        
        Medicine - find new proteins for medicinal uses
        
        Screening - detecting diseases
      - size of genomes can usually be represented as this:
        eukaryotes> prokaryotes> virus and bacteria
        plants just kinda are all over the place due to polyploidy
    - - types of mutations:
        
        point mutations: change in a single nucletide in the base sequence
        -- insertion
        -- deletion
        -- substitution
        -- inversion
        can lead to silent (no change)/ missense (change 1 amino acid)/ or nonsense (premature stop codon)/ frameshift (changes reading frame)
        
        block mutations: change made to a segments of a chromosome:
        -- duplications
        -- deletions
        -- inversions
        -- translocations
      - can lead to disorder such as:
        
        sickle cell anemia
        caused by a mutation on the non-trasnscribed strand GAG to GTG, which causes the 6th codon on the mRNA strand to become GAG to GUG, changing it from glutamic acid to valine
        
        this causes the proteins in RBC to be insoluble and fibrous, causing it to have a sickle shape, be weak, inefficient in carrying oxygen and easily clot up.
        however those who are heterozygous for sickle cell anemia enjoy heterozygous advantage against malaria, as the virus breeds in RBC
      - somatic (meaning body) mutations:
        
        cannot be inherited
        
        occurs in one body cell
        
        only tissues derived from it are
        
        germline (meaning being able to develop into a new thing + successive) mutations:
        
        can be inherited
        
        occurs in gametes
        
        every cell affected
      - mutations can be induced or spontaneous:
        
        they can be induced through mutagens:
        -- raditation - gamma UV xray
        
        chemicals - reactive o2 species
        -- biological agents - bactieria / virus
        (carinogens are an exmaple of a mutagen)
        
        link to chernobyl and hiroshima, caused increase in cancer develpment, reduced t cell counts, organ specific issyes, thyroid disease, chernobyl still is unsafe for human living
    - - does not determine genetic complexity (i.e. tomatoes have 24 chrom, 950 million b.p and 32000 genes)
        
        different number of diploids means they cannot create offspring, if offspring is created, then they wlll be infertile
    - - natural cloning: most plants, all bactiera, most fungi and come animals all have antural ways to clone
        animals:
        
        binary fission: dividing the self equally by two, producing identical daughter organisms
        
        budding: cells split off the parent organisms, generating a smaller daughter org that will eventually seperate
        
        fragmentation: new org grows from seperated fragement of parent (starfish)
        
        parthogenesis: embroys formed from unfertislized ova, female makes diploid eggs
        
        plants:
        
        are able to do vegatative propagation whereby small pieces can grow indepenetly, almost all root and shoot plants can do this (e.g. onion ad garlic bulbs are all geneticlaly identcal), underground stems can form new plants such as potatoes, and runners (horizontal stems) can grow roots and shoots out of them, also some do it via spores
        
        humans:
        
        monozygotic : 1 fertilisation occurs from on zygote(100% dna shared), split into two genetically identical embryos
        
        dizygotic are not identical twins but are t wins, two seperate fetrilidations (50% of dna shared)
        
        artificial cloning: can be done in two ways:
        
        by splitting a normally fertilised embryo in the lab, as embryos are pluripotent therefore they should be able to develop into a whole organism, the downside of this is that it needs to have early in the developmental cycle (cycle 8) and you do not know what the offspring will look like
        
        another way is somatic nuclear transfer
  - - - chromosomes:
        
        have a pinching point called a centromere, the short arm is p and the long arm is q.
        
        each chromosome has unique banding patterns
        
        as we inherit both of our parent's chromosome, we have two sets of each allele, these two chromosomes are called homologous chromosomes (same structure and loci of the gene, diff alleles)
        
        genes can be located using 3 categories, number of the chromosome. arm, g-band location
        
        the position of the centromere of a chromosome can be split in 4 categories:
        
        meta-centric - equal p and q
        
        sub meta centric - basic chrom shape, p a bit shorter than q
        
        acrocentric - p much shorter than q
        
        telocentric - no p
      - DNA of eukaryotes is linear and bound with histone proteins for storage, they bind with an octamer of histones to form a nucleosome: