Your First Will & Testament – Genetic Inheritances

What you are is controlled by two factors – your genetic inheritance from your parents and the environment in which your live. This is called the Nature-Nurture division and is the basis of modern genetic understandings. You will have noticed that you have certain physical similarities with other members of your family – people may say you have “your mother’s ears” or “your father’s hands”. This doesn’t mean that you actually have your parents’ appendages, more that they are physically similar – that you have inherited those characteristics. This was first investigated by an Austrian monk, Gregor Mendel who spent much of his time cross-breeding plants to discover how these inherited factors would relate to each other. He was the first to identify the concepts of dominant and recessive characteristics – i.e. that an organism could have a genetic trait which was not expressed in its physical appearance.

I have assembled a sequence of videos that cover the content of the course if you wish to watch them; they are organised as a playlist – here are the tracks, should wish to view a particular video:

  1. Introduction to Genetics – What are Genes
  2. Introduction to Genetics – Genes and Alleles (SNPs)
  3. Introduction to Genetics – Where do Genes come from
  4. Introduction to Genetics – What is  Phenotype
  5. Sci 10 – Genes & Proteins
  6. Sci 10 – Genes & Proteins pt2
  7. Sci 10 – Gregor Mendel
  8. Sci 10 – Punnet Squares 1
  9. Sci 10 – Punnet Squares 2
  10. Sci 10 – Codominance
  11. Sci 10 – Blood Types
  12. Sci 10 – Incomplete Dominance
  13. Brainiac – The Genetics of Stinky Urine.

Here is the first one:

Here is the playlist of all the rest.

You may have noticed the family tree in that last video. We call this a pedigree and it is possible for various traits to be handed down from parents to children, but it is possible for a trait to skip generations or be present in only some offspring from a particular generation. Understanding how this happens is called Pedigree analysis, and this slideshow should help you understand how to identify the type of inheritance at play in any given situation.

Finally, if you’ve read all this way, you may want to have some “fun” with this blood typing game. See if you can avoid killing all the patients…

See you in class!

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11 Comments on “Your First Will & Testament – Genetic Inheritances”

  1. Mark Says:

    hi mr G,

    will there be a large section in the test on pedigrees?
    cause i dont really understand that well.

    mark

  2. Mr G Says:

    Hi Mark,

    Yes, there will be some questions on Pedigrees. Have you looked at the slideshow in this post?

    MrG.

  3. Mark Says:

    Alright

    i did some extra reading, so i should fine

    thanks

    mark

  4. Mark Says:

    mr g

    do we need to know about dihybrid crosses or just mono hybrid crosses for this test?

    mark

  5. julian. Says:

    hey Mr G
    how long is our karyotype letter supposed to be?
    and when is it due? ==”

    ciao

  6. Simone Says:

    Hey Mr. Grichting it’s Simone here
    I found this on the internet and I thought it was really confusing… I was researching for my Karyotype which is Chromosome Smear 9 and it came up with this…
    hope u can understand it better than I did and maybe u can explain it to me?

    Embryo selection

    The parents of a five year old girl who has leukaemia are pleading with the Assisted Reproduction Authority to be allowed to select an embryo that will produce a brother or sister who can save her life. In an Australian test case Leonard and Celeste Ryan want to use IVF combined with gene testing (Preimplantation Genetic Diagnosis or PGD) to create and genetically select embryos that are a match for their five year old daughter Sophie, who has acute lymphoblastic leukaemia. These services have recently become available at the Simfiscal Fertility Clinic.

    Sophie has already undergone treatment including intensive chemotherapy, where drugs were injected into her bloodstream everyday during long hospital stays. “To have to watch your child suffer through this is every parent’s nightmare,” says Mrs Ryan “Sophie just wants to be like the other kids. Now that she has had a relapse the best chance for our Sophie is a cord blood cell transplant from a matched brother or sister”. Mrs Ryan said that she and her husband wanted another child anyway, provided the child was healthy and if the child could help Sophie what a blessing that would be.

    If approved, the Ryan’s would create embryos using their own eggs and sperm via IVF. Following embryo screening, Celeste Ryan would have the ’selected embryo’ (which would be matched to treat Sophie) implanted. If all goes well with the pregnancy, stem cells from the umbilical cord would be collected after the birth and infused into Sophie’s blood stream. Despite sounding simple, recent statistics suggest that only one in five IVF cycles results in pregnancy. In a similar case, an American couple underwent four IVF treatment cycles, and of five suitable embryos only one survived.

    In the ethical debate following the news of this proposal, critics have accused scientists of playing God in marrying genetic testing and IVF in this way and of creating “designer babies”. Some ethicists expressed concern that this child will not be loved for itself but simply for the spare parts provided.

    Dr Lance Simfiscal from the Simfiscal Fertility Clinic denies that this procedure is genetically engineering “designer babies”. “It is about diagnosis, treatment and saving a life, we are not designing anything” Dr Simfiscal said. Sophie’s father Leonard Ryan said, “it is very easy to conjure up all kinds of objections when you haven’t been put on the spot yourself. The desire we have to help our little girl is one of the deepest human impulses and people shouldn’t dismiss this so easily.” They ask if when the embryo is being selected it could be a male embryo with matching tissue type to Sophie.

  7. Lynette Says:

    Ben said that we’re allowed to hand in our Karyotyping answers on a separate sheet of paper. Is this true? If not, will we be marked down for lack of detail?
    :S

  8. Lynette Says:

    Also, my chromosome is most commonly linked with CML. Can I give details on the etiology of CML, or do I have to also write about the other diseases that are less commonly associated with the philadelphia chromosome?

  9. Lynette Says:

    Does my answer for question one have to refer to the differences between the philadelphia chromosome and a normal karyotype, or should my answer be specific to the karyotype that I’ve been given? I think the one I have differs slightly to the normal version of philadelphia because other websites say that the translocation between 22 and 9 should be reciprocal – but on my sheet a bit of 9 is on 22, but no part of 22 is on 9.

  10. Mr G Says:

    Hi Lynette,

    Sorry about the delay! I didn’t see your comments. You must submit your karyotype (organised chromosomes) separate to your letter. You can use the etiology of CML – but keep it short! Use the philadelphia standard instead of yours if that helps.

    MrG.


  11. […] get too far into this topic, you may want to revise the important concepts of Genetics. Here is a post that covers the genetics topics – I strongly suggest you go back and read it (and watch the […]


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