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Genetic Facts and Fallacies

Discussion in 'General Chat' started by 2020hindsight, Mar 15, 2008.

  1. 2020hindsight

    2020hindsight

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    http://www.epasd.org/55981257613530/lib/55981257613530/Genetics_Packet_student_packet.DOC

    A quick quiz -
    it's about "you", your mum and your dad
    or if you prefer - about you, your wife and your kids ;)

    GENETIC FACTS AND FALLACIES QUIZ

    T F 1. Certain acquired characteristics, such as mechanical or mathematical skill, may be inherited.

    T F 2. Identical twins are always of the same sex.

    T F 3. Fraternal twins are more closely related to each other than to other children in a family.

    T F 4. The father determines the sex of a child.

    T F 5. Each parent contributes half of a child’s genetic makeup.

    T F 6. Certain drugs or alcohol can cause birth defects in the fetus.

    T F 7. Colorblindness is more common in males than in females.

    T F 8. A person may transmit characteristics to offspring, which he, himself does not show.

    T F 9. Certain hereditary characteristics are influenced by the blood.

    T F 10. Identical twins are more closely related than fraternal twins.

    T F 11. Certain inherited traits may be altered by the stars, moon, or planets early in development.

    T F 12. Males are biologically stronger than females.

    T F 13. The tendency to produce twins may run in families.

    T F 14. A craving for a food such as strawberries may cause a birthmark on an unborn child.

    T F 15. Many of a person’s inherited traits are not apparent.

    T F 16. The parent with the stronger “will-power” will contribute more to a child’s inheritance than the other parent.

    T F 17. If a person loses a limb in an accident, it is likely that he or she will have a child with a missing limb.

    T F 18. The attitude of the parents toward each other influences the emotional makeup of an unborn child.

    T F 19. Children born to older parents usually lack the vitality of those born to younger parents.

    T F 20. The total number of male births exceeds female births each year.

    T F 21. If a male mongrel dog mates with a pedigree (show quality) female dog, all future litters will have some characteristics from the mongrel male.
     
  2. 2020hindsight

    2020hindsight

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    FUNDAMENTALS OF GENETICS

    HEREDITY”” The passing of traits from parents to offspring - Transmitted by means of information stored in molecules of DNA

    GENETICS--- Scientific study of heredity- Based on knowledge that traits are transmitted by chromosomes
    Chromosomes carry units of hereditary information called ___________

    Since an organism receives genes from both parents it is not exactly like either parent but like each parent in some ways

    ENVIRONMENT--- All the outside forces that act on an organism. Affects the development and later life of an organism as well as the expression of hereditary traits

    HEREDITY & ENVIRONMENT--- are the two great influences, acting together all through you life, that have made you what you are at this moment.


    GREGOR MENDEL -- “_____________________________” – Austrian monk – 1865
    --his research with garden peas led to the discovery of the basic principles of heredity
    --Garden peas were a good choice for experimentation because:
    1. They can be cultivated quickly
    2. They display several traits in one of two contrasting forms:
    Height””tall/short seed color””yellow/green
    3. They normally self-pollinating plants are very easy to cross- pollinate.
    -- Mendel used logical experimental methods and kept careful records


    MENDELIAN GENETICS OVERVIEW

    We humans each have two sets of _____chromosomes – _____ chromosomes total.

    Our __________________ are made up of our genes, which are pieces of DNA that code for certain traits.

    For example, both of our chromosome’s might contain the genes for hair texture or height or maybe even intelligence.

    The different forms or types of a specific gene are called ___________. For example, a GENE for eye color might have a blue allele, a brown allele, and a green allele. In plants, a gene for flower color might have a yellow allele and a white allele.

    Because our chromosomes are in two sets, we have two copies of each gene, one from our mom and one from our dad.

    If both of our parents gave us the same type of gene – the same allele – then we are _____________________________or pure (on both sets of our chromosomes, on both sets of genes, the allele is the same).

    If one parent gave us one type of gene and the other parent gave us a different type, then we are ___________________________ or hybrid – we have two different alleles.

    With MENDELIAN traits (the type of traits that Mendel studied), heterozygotes DO NOT have a _____________of the two alleles.

    Instead, one type of allele dominates – we show the characteristics of this allele only – it is the _________________ trait. The other version of the trait is still there on half of our chromosomes (so we might still pass it on to our children, depending on meiosis) BUT it doesn’t affect us right now””it is __________________

    Whether we are heterozygous, homozygous with the dominant trait, or homozygous with the recessive trait is what’s called our ____________________ (type of genes that we have).

    Which trait we physically show is our ______________________ (the type of allele that is expressed.)

    For example, if the dominant allele of the eye color gene is brown and the recessive allele of the eye color gene is blue, then the person could have …

    Two blue alleles –bb””(one from mom, one from dad), in which case the genotype would be ______________________________and the phenotype would be ________________


    Two brown alleles –BB””(one from mom, one from dad), in which case the genotype would be ___________________________________and the phenotype would be ______________


    One brown and one blue allele –Bb””(one form mom and one form dad) so the genotype would be ______________________ and the phenotype would be _____________________

    When only one trait is being studied in a genetic cross, it is called a monohybrid cross. When parent organisms, called the P generation, are crossed, the resulting offspring are the first filial, or F1 generation. When organisms of the F1 generation are crossed, their offspring make up the second filial or, F2 generation.



    MENDEL’S 2 LAWS:

    1. _________________________________= Explains the disappearance of a specific trait in the F1 generation and its reappearance in the F2 generation

    2. _________________________________= Explains that different traits are inherited independently if on different chromosomes
    - Wrinkled seeds do not have to be yellow. They can be green.
    - A gamete with RrYy
    o R and r – separate into different gametes
    o Y and y – Separate into different gametes
    - They can then recombine 4 ways to form gametes:
    RY Ry rY ry


    INHERITANCE OF HUMAN TRAITS
    DOMINANT/ RECESSIVE

    Dark hair/ Light hair
    Non-red hair/ Red hair
    Curly hair/ Straight hair
    Widows peak/ Straight or curved hairline
    White forelock/ normal hair
    Body hair/ Scant body hair
    Piebald skin/ normal skin
    Freckles/ Normal
    Dimples/ No dimples
    Brown eyes/ gray or blue eyes
    Hazel or green eyes/ Gray or blue eyes
    Farsighted/ Normal eyesight
    Normal eyesight/ Nearsighted
    Large eyes/ Small eyes
    Long eyelashes/ Short eyelashes
    Broad nostrils/ Narrow nostrils
    Roman nose/ Straight nose
    Large nose/ Small nose
    Free ear lobe/ Attached ear lobe
    Extra toes & fingers/ Normal fingers
    Web fingers/ Normal fingers
    Bent little fingers/ Parallel little fingers
    Left over right thumb/ Right over left thumb
    A or B blood/ O blood
    RH+ blood/ RH- blood
    Normal clotting/ Hemophilia
    Normal / Allergy
    Migraine headaches/ Normal headaches
    Normal intelligence/ Feebleminded
    Harelip & cleft palate/ Normal mouth
    Tongue roller/ Non-roller


    --Genetic messages determine what organisms _______ become
    --The interaction of messages and the environment determines what organisms ______ become
    --Organisms inherit _________________________, not traits!
    --Traits develop when genetic messages interact with the environment


    HUMAN GENETICS
    Fraternal vs. Identical Twins
    _____________________ develop from a single fertilized egg that splits shortly after fertilization

    Since they developed from the same egg they have exactly the same genetic makeup.

    _________________________ develop from two eggs that are fertilized by different sperms. They are completely different people

    By studying identical twins, geneticists have learned that genes seem to have a greater influence than the environment on such traits as height, weight, blood pressure, speech patterns, and gestures. They have also discovered that genes play a role in some medical problems once thought to be caused only by environmental factors. For instance, genes can cause a susceptibility to diseases such as diabetes and certain types of cancer.

    Heredity and the Mind
    -there is some evidence intelligence is related to genes
    -strong evidence that certain kinds of retardation have a genetic basis
    -maniac-depressive psychosis and schizophrenia are both thought to be inherited at least to some degree

    Inherited Diseases
    -infections and infectious diseases cannot be inherited
    -certain chemical conditions of the cells and body tissues important in resistance against
    infections may be inherited.
    -diseases resulting from abnormal structure or function of body organs are more likely to be hereditary

    - some diseases that may be associated with genes are:
    -diabetes – respiratory allergies – asthma – bronchitis – nearsightedness – farsightedness – night blindness

    Sex Determination
    Sex chromosomes – determine the sex of an individual
    --the X chromosomes (XX) produce a ________________
    --an X chromosome paired with a Y chromosome (XY) produces a ___________
    --since only a male can produce a gamete bearing a Y chromosome, the father determines the _________ of the child
    --but it is also interesting to note that since the X chromosome contains additional genetic
    information that the Y chromosome does not have a male child actually inherits more genetic information from his mother than his father (a very tiny amount)

    Sex-Linked Traits
    --traits that occur more frequently in one sex than another such as color blindness and hemophilia in males

    --occurs because other genes besides the alleles for sex are located on sex chromosomes
    --they are recessive to the normal condition and the Y chromosomes appear to lack genes for these traits
    --these traits generally do no show up in females
     
  3. julius

    julius

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    where are the quiz answers?
     
  4. 2020hindsight

    2020hindsight

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    sorry julius
    out there in google land
    (think of it as a crossword - "Solution in Next Week's Sun Herald" etc) ;)
    or tomorrow whatever
    (PS It's obvious I suspect that I don't necessarily know the answers, lol)
     
  5. Julia

    Julia In Memoriam

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    2020, pretty pointless posting these quizzes without giving a link to the answers or preferably including answers on the thread.
     
  6. 2020hindsight

    2020hindsight

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    OK here are my guesses:-

    T 1. Certain acquired characteristics, such as mechanical or mathematical skill, may be inherited.

    T 2. Identical twins are always of the same sex.

    F 3. Fraternal twins are more closely related to each other than to other children in a family.

    T 4. The father determines the sex of a child.

    T 5. Each parent contributes half of a child’s genetic makeup.

    T 6. Certain drugs or alcohol can cause birth defects in the fetus.

    T 7. Colorblindness is more common in males than in females.

    T 8. A person may transmit characteristics to offspring, which he, himself does not show.

    F 9. Certain hereditary characteristics are influenced by the blood.

    T 10. Identical twins are more closely related than fraternal twins.

    F 11. Certain inherited traits may be altered by the stars, moon, or planets early in development.

    T 12. Males are biologically stronger than females.

    T 13. The tendency to produce twins may run in families.

    F 14. A craving for a food such as strawberries may cause a birthmark on an unborn child.

    T 15. Many of a person’s inherited traits are not apparent.

    F 16. The parent with the stronger “will-power” will contribute more to a child’s inheritance than the other parent.

    F 17. If a person loses a limb in an accident, it is likely that he or she will have a child with a missing limb.

    T 18. The attitude of the parents toward each other influences the emotional makeup of an unborn child.

    F 19. Children born to older parents usually lack the vitality of those born to younger parents.

    T 20. The total number of male births exceeds female births each year.

    T 21. If a male mongrel dog mates with a pedigree (show quality) female dog, all future litters will have some characteristics from the mongrel male.
     
  7. roland

    roland

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    hohum - sort of expected considering the originator of the thread - I resisted looking and am now disappointed for doing so.

    How is Julia, by the way?
     
  8. Garpal Gumnut

    Garpal Gumnut

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    12. Males are biologically stronger than females.

    How do you define biologically stronger?

    gg
     
  9. 2020hindsight

    2020hindsight

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    gee whiz roland
    getting a bit personal there ;)

    Hey mods - please close this thread, Julia and Roland are bored lol.

    btw, Ethics in Genetics is probably the most controversial field you could consider taking on. This thread could be a real hum-dinger ;)

    But that assumes that you show a little bit of mmm interest / intelligence / all of the above.

    Here are some of the directions Genetics leads...

    http://www.lessonplanet.com/search/search?keywords=Genetic&rating=4&gclid=COnLr-mHj5ICFSAWawodFGo1_A
     

    Attached Files:

  10. 2020hindsight

    2020hindsight

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    PS I'm with Phillip Adams, who "simply cannot understand how people could be bored with life given the beautiful mysteries and coincidences behind it all"

    https://www.aussiestockforums.com/forums/showthread.php?p=201776&highlight=valley#post201776

     
  11. BIG BWACULL

    BIG BWACULL

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    Look in your pants if you have a shlong:eek:you are biologically stronger:eek:
    That didnt answer the question:confused: OH Well:rolleyes:
     
  12. 2020hindsight

    2020hindsight

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    As for that quiz - obviously it's pretty basic..
    But you have to start somewhere.


    Like 1-3 are obvious
    Here's the reason behind 4... (as if anyone didn't know) :eek:

    http://biology.about.com/od/basicgenetics/a/aa071705a.htm
     
  13. 2020hindsight

    2020hindsight

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    ahh - good point gg ;)

    another of those ambiguous questions it seems ....

    seems that women are the more "biologically strong" - if that means best chance of "making it" through the birth process.

    but men, being the more muscular, are literally stronger.

    http://www.answerbag.com/q_view/644520

     
  14. Doris

    Doris

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    Good question GG...

    2020 this is the only one of your answers I disagree with.

    Males are physically stronger due to their muscle mass compared to females.

    Not only are more males born compared to females but I recall reading that there are a lot more males conceived compared to females as there are more male miscarriages than female.

    I reckon males traditionally have shorter longevity than females as they tended to let the women do the work (housework = exercise) and they abused stress, junk food, alcohol and cigarettes more then women. ???

    Still... biologically, females are stronger!

    I've always been fascinated by the fact that, over the centuries, when males went off to war and were slaughtered in great numbers, the number of males born in the next x years increased dramatically to make up the loss to try to even the M/F balance. Isn't it amazing how half the population is male? Except in outback towns! :)
     
  15. 2020hindsight

    2020hindsight

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    Doris - yep I have seen the error in my answer.

    Gotta feeling I'm wrong about 21 as well.
    You keep breeding a mongrel's descendants with purebreds, you could presumaby end up with a purebred?
    EXCEPT that the odds would be trivially small.
     
  16. Garpal Gumnut

    Garpal Gumnut

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    You also might end up with a "new" pure breed.

    gg
     
  17. Doris

    Doris

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    When I was a kid I always wondered why boys had nipples... until I learnt the above at school. Then I figured out that all fetuses/people have a basic female body and the Y chromosome causes the hormones that make changes to produce the male traits!

    Makes Eve being made from Adam's rib hard to digest...

    Isn't it five generations to go before the Y chromosome is non-existent?
     
  18. Doris

    Doris

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    This reminds me of a situation near Biloela where an aboriginal guy killed his aboriginal wife for playing up on him, as she'd had a red-haired, blue-eyed son. It was later found that her grandfather was an itinerant Irishman! The husband would have had a recessive blue gene for this to happen... ignorance is not bliss.

    When I was a kid a Greek guy down the road told his wife not to come home if their third child was another girl! He actually beat her up in hospital when it turned out to be another girl!!!

    I can't recall... but aren't there about 28 genes that influence eye colour? Not simply one. So it'd take a long time to produce a 'purebred look' which would always have some DNA coming through from the mongrel.
     
  19. 2020hindsight

    2020hindsight

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    personally I think "crossbred" dogs are the best ;)

    And that would also go for mixed race people. That's not an insult to anybody btw. Best of both parents ;)

    heck I'm 50% pom, 25% Scot, 12.5% Irish, 6.25% German, 18.5% mathematician etc etc, probably a bit of Swahili as well etc.

    As if any of us are "purebred" - What is a "purebred" person anyway?

    IMO, some of the most beautiful women in the world are of an absolute mixture of races. (Eurasian etc). :)

    Wouldn't you like to meet all your 64 (?) great-great-great-great grandparents ... line em up ... and talk to them for a while, and try to work out from whom you received which genes.

    I sometimes ponder that over a beer. :cool:
     
  20. 2020hindsight

    2020hindsight

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    doris, yep.
    and btw, my 3 kids all have different hair colour lol.

    (it's ok though, the milkman was bald ;))

    at least 3 genes make eye colour - you're right.

    http://en.wikipedia.org/wiki/Eye_color
    What was the joke about the black man goes to the white priest, furious that his wife must have been playing round - because she's just borne him a white child.

    So the priest expains "ahh Rastus, that's just an albino child"
    "what's that" sez Rastus
    "Well" sez the priest - see that herd of sheep in yon paddock - see how some are black and some are white?"

    and before he can make the point, Rastus interrupts
    "Hey father - you don't tell anyone and I won't either ok?" ;)

    PS I tend to have red eyes on the weekends for some reason. : 2twocents
     
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