Please enable JavaScript.

Coggle requires JavaScript to display documents.

Inheritance - 2 - Coggle Diagram

- - - - such genes are called sex-linked genes
        
        characters they regulate are sex-linked characters
        
        pattern of inheritance of these characters is called sex-linked inheritance
  - - - we also talk about T.H. Morgan
        
        nickname - lord of flies
        
        used to work with fruit flies - Drosophila melanogaster
        
        coz they were available in a number of varieties
        
        can easily mutate the genes too
        
        fly has 4 pairs of chromosomes
        
        we share 60% of dna with it
        
        they can inherit autism, and similar diseases, similar to humans
  - - - usually only got red eyed fruit flies
        
        but one time he got a white coloured make fly
        
        conformation bias - begin to believe the data
        
        but he didn't give in to conformation bias
        
        cross 1 - homozygous female
  - - - 2 points
  - - - coz gene for regulating is on the x chromosome
  - - - gametes of only one type
    - - 50% X, 50% Y
  - - - in hetero and homo conditions
    - - expressed only in homozygous conditions
        
        in terms of females
  - - - sex-linked inheritance - aka criss-cross inheritance
  - - - 1
        
        give a clear idea of relationship between genes are sex chromosomes
      - 2
        
        gene for any sex linked character is on the X chromosome
      - 3
        
        most important
        
        idea about mechanism behind inheritance of sex linked disorders
- - - - but sometimes, these are so many characters which are cont
        
        the diffferent interactions are intergenic interactions
        
        the type of interactions that take place between
  - - - affecting the same character but producing different degrees of expression
        
        in different individuals of the same species
  - - - can be related by dominant, recessive or codominant
- - - - traits
        
        purple
        
        white
    - - traits
        
        terminal
        
        axial
    - - yellow
      - green
    - - round and smooth
      - wrinkled
    - - yellow
      - green
    - - inflated
      - constricted
    - - tall
      - dwarf
  - - - the trait that gets expressed in the f1 gen is the dominant allele
        
        similarly, the allele that is not seen in the f1 gen but is seen in the f2, it is the recessive allele
        
        the trait that is hidden in the f1 but is expressed in the f2 along with dominant is called the recessive trait
  - - - members of the determiners remain together in the f1 hybrid
        
        but they begin to separater from one another at the time of gamete formation
        
        there is equal possibility of each member to get into each gamete
        
        because each member goes into one gamete, like Tt - fforms T and t gametes
  - - - 1:2:1 (genotypic) or 3:1 (phenotypic)
- - - - they just aren't able to perceive normal differences in. colour under normal lighting conditions
        
        when a person is colour blind, there are only 2 colours they can't see
        
        red - protonopia
        
        when they can't recognise red
        
        green - deuteranopia
        
        can't recognise green
  - - - there are photo sensitive cells
        
        named on basis of shape and location
        
        type located towards periphery - rod shaped
        
        called rods
        
        located central to retina - cone shaped
        
        cones
  - - - associate it to different colours
- - - - by modifying, you can still account for each one
        
        neo-mendelism
  - - - intragenic interactions
        
        when on the same gene
    - - inter-genic interactions
  - - - the alleles were related to each other -
        
        one is dominant and one recessive
        
        when the genes of an allelomorphic pair are not related to each other as dominant or recessive but when they are present in the f1 hybrid
        
        they will express themselves in such a manner that the f1 hybrid exhibit traits that are intermediate to the 2 parents
        
        called
        
        blending inheritance
        
        a blend of the traits
    - - genus of flowering plants seen in rocky terrains
      - called snap dragons
        
        arrangement of anthers and flowers
        
        petals close and open like the mouth of a dragon
      - available in 2 colours
        
        red and white
        
        red has an allele for red
        
        white has an allele for white
- - - - but epistasis
        
        when 2 genes interact, it results in the expression of one gene masked by another gene
  - - - condition where recessive allele present on a locus of one chromosome will inhibit the expression of both the dominant and the recessive allele present on a different locus on a different chromosome
      - eg: andalausian fowls
        
        aka legons (horn like projection at the back of its leg
        
        eg: gene that codes for colour is B (colour of feathers)
        
        dominant. - B and recessive - b
        
        if a chicken gets dominant, BB is black
        
        but if hen gets recessive bb - it is white
        
        expression on one allele is masked by another
        
        another gene - F and f
        
        present on a different locus and differnet chromosome
        
        dominant allele on different chromosomes affects another - B b
        
        coz of presence of epistatic gene - F, if the hen still gets the bb
        
        doesn't result in black hens
        
        1 more item...
      - eg
        
        puppy inherited dominant allele, has a black coat
        
        if recessive allele - brown coat
        
        B and b
        
        recessive f inhibits B and b
        
        inhibits B - black
        
        1 more item...
        
        black male dog (BBww)
        
        fawn female dog (bbWW)
        
        child is black (BbWw)
        
        deviation of mendelism
    - - A dominant allele present on one locus on one chromosome is able to hide or suppress the expression of both dominant as well as recessive alleles present on a different locus of a different chromosome, which is called dominant epistasis
      - colour of cucumber
        
        seen in 3 colours.
        
        white - dominant W
        
        Yellow - dominant G
        
        Green - recessive g
- - - - show the presence of genes
        
        coding for somatic characters, physical features,
    - - show the presence of genes, but they code for/ determine the sex of an individual
        
        X and Y
  - - - usually size is represented by mbp - million base pairs
        
        X has a size of 155mbp
        
        Y is only 59mbp
  - - - of 25000 genes, X chromosome has 2000 genes
      - Y has 231 genes
  - - - X chromosome shows 3% of total dna
      - Y is 2% of total DNA
    - - they are more genetically stable
        
        eg colour blindness and haemophilia
- - - - length of stem is most famous
        
        plants with length - 100-120 cm
        
        long/tall
        
        22-44 cm
        
        dwarf
      - used cross pollination
    - - f1 gen was only tall pea plants
        
        f1 tall plant and self pollination
        
        got tall and dwarf plants in f2 gen
        
        in ratio 3:1
        
        3 tall and 1 dwarf
    - - he took the f1 gen and subjected it to self pollination
        
        and he got tall and dwarf in ration 3:1
    - - but took tall (homoz), and all were tall
        
        took next tall pea plants - self pollination - and he got tall and dwarf pea plants in tha ratio 3:1
        
        tall and dwarf plants - got 1/3 tall, and 2/3 tall and dwarf
- - - - the expression of any/every genetic character is controlled by a set of determiners or a set of factors
- - - - brown and white
        
        brown alleles and white alleles
        
        offspring could get brown cow with white spots
        
        or a white cow with brown spots
        
        they express themselves independently of each other
        
        they are called roan cattle
    - - cross
  - - - A, B, AB, O
        
        based on sugar polymers on plasma membrane of rbcs
        
        also have proteins - so they're actually proteins
        
        coded by a gene
        
        gene can be I or L
        
        I - Immunoglobulin
        
        L - Landsteiner
        
        we'll use I
    - - I^A
    - - I^B
    - - I^A and I^B
    - - no antigens
    - - but in blood groups, there are 3 alleles
        
        I^A, I^B, I^O
        
        an individual must have any 2 alleles so the indivudual will have a specific blood group
    - - but O is always recessive
        
        A and O - A is expressed
        
        B and O - B is expressed
- - - - coz its blood
        
        it must be Hb^A and Hb^A
        
        normal RBCs - a biconcave disc
  - - - decreases the surface area:vol ratio
        
        clog capillaries and cause a clot and lots of pain
        
        stops the blood flow
        
        if in the brain, they cause strokes, haemorrhages
  - - - normal haemoglobin
    - - acute sickle cell anaemia
    - - heterozygous
        
        still sickle cell anaemia
        
        if the concentration is high, its like hbs hbs
        
        but if its low, its not detectable
    - - hba hba - gets malaria
      - hbs hbs is actually immune to sickle cell anaemia
      - buttttttt hba hbs is immuneeeee
- - - - bring about an increase in intracellular nitrous oxide
        
        when high conc no2, triggers a signal transduction cascade
        
        series of oxidative reaction
        
        involving amino acid - tyrosine and gene tyr
        
        to form melanin
        
        gives colour to skin
  - - - not a disease
        
        an inherited condition caused by the mutation of a gene
        
        the tyr gene
        
        present on chromosome 11
        
        (autosome)
    - - but coz of mutation, person lacks pigments on skin hair and eyes
  - - - but we need only one
        
        oculo-cutaneous albinism
        
        symptoms
        
        results in a faulty protein - not really melanin
        
        person is photophobic/sensitive
        
        normal people have retinal pigment epithelium
        
        need it to absorb refelcted light
        
        but for them its not well developed
        
        melanin in eye is not working properly/ not developed
        
        1 more item...
        
        generally suffer from strabismus
        
        cross-eyed
        
        show presence of a condition called nystigmus
        
        random/rapid eye movements
        
        coz of no melanin on skin
- - - - had 9 children
        
        42 grandchildren