LULU asked in Science & MathematicsBiology · 1 decade ago

i need to understant where to Put the dominate and the ressive/like either on top,sides,.is there hints..?

is there any hints i can use for my exam/qizz 2morrow? and it's about monohybrid and dihybrid? my problem is that i don't know where to put the capital A or little a ,,are they should be on top bottom or mabye double aa on the side or vice versa?

please iam sooooooo confused n my quizz 2morrow very important!!!

please i need help


guys i need to know like how? how and when to put mabye one capital and one small on the side or 2 capitals or vise versa.

please my stomach hurts/help me

3 Answers

  • 1 decade ago
    Favorite Answer

    One parent's alleles go across the top and the other parent's alleles go down the side. The order does not matter.

    So if you crossed AA by Aa you could put A, A across the top and A, a down the side (or vice versa) to calculate your square (resulting in 4 offspring).

    If it is a dihybrid cross (eg: AABB x AaBa) you would list AB, AB, AB, AB across the top and AB, Ab, aB, ab down the side (for 16 offspring)

    Usually it is the male across the top and the female down the side but that is not important if you are just trying to calculate probabilities etc.

    I hope that makes sense.

  • 1 decade ago

    yes Maegan b is right

    it really does not matter where you put the recessive or the dominant

    A A this is from a homozygous dominant person AA

    a Aa Aa

    a Aa Aa

    and aa is from a homozygous ressecive

    if it's from a heterozygous Aa and Aa the chart will be lyke this

    A a

    A AA Aa

    a Aa aa

    therefore there is a 50% chance of Aa heterozygous offsprings

    25% chance of homozygous reccesive aa

    25% chance of homozygous Dominant AA

    succes on your test tomorow

  • 1 decade ago

    Maybe this will help...

    A A

    a IAa_IAa_I

    a IAa_IAa_I


    A a

    A IAA_IAa_I

    a IAa_Iaa_ I

    i tried? :)

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