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trihybrid ratios

Genetics as it applies to evolution, molecular biology, and medical aspects.

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trihybrid ratios

Postby lbc1127 » Thu Apr 13, 2006 10:40 pm

alright i am doing a chi sqaure analysis for my genetics class. but before i can procede, i need to know what the expected results would be between a heterozygous and a homozygous recessive plant in a trihybrid cross.what would the ratio be?? i can't for the life of me figure this out..PLEASE HELP!!!
Last edited by lbc1127 on Fri Apr 14, 2006 12:03 am, edited 1 time in total.
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Postby Bio-Hazard » Thu Apr 13, 2006 10:46 pm

Google is your friend: http://www.google.com/search?hl=en&q=pu ... calculator

Don't have time right now to give a full reply.
Google: Hybrid genetics ratio
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Postby lbc1127 » Thu Apr 13, 2006 10:56 pm

is there an expected ratio for a trihybrid cross between a heterozygous and a homozygous recessive plant? i only need to know the ratio. ive tried google and everywhere else, but i cant find anything on a trihybrid cross and if i do it only deals with two heterozygous plants.
here is the link to the assignment if it helps. im not asking for answers, just a little bit of info....
http://www.cod.edu/people/faculty/fanch ... Home02.doc
Last edited by lbc1127 on Fri Apr 14, 2006 12:37 am, edited 1 time in total.
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Postby buffylova1 » Fri Apr 14, 2006 12:04 am

I'm doing the same type of thing, and having major problems. I'm only in the 7th grade, but these damn advanced classes suck. If I could, I would help you....but...uh...major problems of my own. :shock:
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Postby lbc1127 » Fri Apr 14, 2006 1:12 am

anything i can help with?
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Postby Bio-Hazard » Fri Apr 14, 2006 12:54 pm

Which number are you doing?

There is a genotypic and phenotypic ratio for a trihybrid cross.


For example, a trihybrid cross would require a Punnett square with 64 spaces! (If you don't believe me, try it for yourself.) This gets to be confusing, and its easier to keep things straight using the forked line method, because it deals with phenotypes rather than genotypes.

- http://www.emunix.emich.edu/~rwinning/g ... endel4.htm

- http://tidepool.st.usm.edu/Crswr/punnett.html
- http://experts.about.com/q/Genetics-179 ... -Cross.htm
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Postby lbc1127 » Mon Apr 17, 2006 8:51 pm

my question concerned question number 1. i can do the chi square test as long as i know what the "expected outcome" of the trihybrid cross between a heterozygous plant and a homozygous recessive plant would. if i understand a trihybrid cross between two heterozygous plants, the expected outcome would be 9:3:3:1. but this is not true for a heterozygous and homozygous recessive cross. what would the "expected" outcome be?
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Postby opuntia » Wed Apr 26, 2006 7:02 am

I hope this is not advertising, here is a great site i found while i was browsing for some A'L revision notes. :)

Regs,
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