Heredity B/Designer Genes C

[PicturePerfect]

@ScienceOlympian:
Cool! I actually got 2nd at Regionals, but the test was SO much easier than States.

[Beastybob12345]

Cool, sounds like a cool event.

[reesabp]

Who writes the NSO DG test? Is it the national event supervisor or is it the Wright State university professor? Also...who is the NSO event supervisor for DG?

[havenbreadfish]

Who writes the NSO DG test? Is it the national event supervisor or is it the Wright State university professor? Also...who is the NSO event supervisor for DG?

I'm not sure if this applies to division C, but for division B the national event supervisor Karen Lankour designs the test. She wrote the Heredity nationals test from 2006, when it was last an event, and the microbe test from last year, both of which were about 11 reasonably long stations. So, the test is probably going to be in this form, and I'm about 90% sure that this be true for Designer Genes as well.

[JhnyT13]

How does a dihibrid cross work? Is it when two organisms with heterozygous mate? I don't really get it....

[crazyfloboe]

How does a dihibrid cross work? Is it when two organisms with heterozygous mate? I don't really get it....

Yes because if you have a homozygous of either parent (compleatly homozygous like BBLL) your trait will always foil out to BL

[gneissisnice]

How does a dihibrid cross work? Is it when two organisms with heterozygous mate? I don't really get it....

Yeah, dihybrid literally means "two HYBRID". What this means though isn't just that you have two heterozygous organisms mating, it means that you have two organisms that are heterozygous for two different traits mating.

A cross like Aa x Aa is a monohybrid cross because there's only one mate. That's easy, you get 1/4 AA, 1/2 Aa, 1/4 aa. A dihybrid cross, like AaBb x AaBb is much more difficult.

Because of genes assort independent of each other, the splitting of the A and B alleles are totally unrelated. Whether the offspring gets B or b from a parent has absolutely nothing to do with whether they got an A or an a. There are a lot more combinations you can get.

From a dihybrid cross, you can get AABB or AABb or AaBB or AAbb or AaBb or Aabb or aaBB or aaBb or aabb as possible genotypes. I believe that ratio is 1:2:1:2:4:2:1:2:1 (I don't know if it's for that exact order, but I'm too lazy to do the math right now). There are 4 possible phenotypes for that; A-B-, A-bb, aaB-, and aabb, with a ratio of 9:3:3:1.

You can even have a trihybrid cross, where you cross AaBbCc x AaBbCc. That takes even longer to do, and you can have even more than that; I've seen a question with 6 different traits. By the time you reach a trihybrid cross, making a Punnett Square gets REALLY difficult and time-consuming, so there's a shortcut you can do. I posted it a few pages back, so read that if you want. If you can't find it, ask me and I'll type it out again.

I probably went into a lot more detail than you wanted, hehe, but I hope that helped.

[JhnyT13]

How does a dihibrid cross work? Is it when two organisms with heterozygous mate? I don't really get it....

Yeah, dihybrid literally means "two HYBRID". What this means though isn't just that you have two heterozygous organisms mating, it means that you have two organisms that are heterozygous for two different traits mating.

A cross like Aa x Aa is a monohybrid cross because there's only one mate. That's easy, you get 1/4 AA, 1/2 Aa, 1/4 aa. A dihybrid cross, like AaBb x AaBb is much more difficult.

Because of genes assort independent of each other, the splitting of the A and B alleles are totally unrelated. Whether the offspring gets B or b from a parent has absolutely nothing to do with whether they got an A or an a. There are a lot more combinations you can get.

From a dihybrid cross, you can get AABB or AABb or AaBB or AAbb or AaBb or Aabb or aaBB or aaBb or aabb as possible genotypes. I believe that ratio is 1:2:1:2:4:2:1:2:1 (I don't know if it's for that exact order, but I'm too lazy to do the math right now). There are 4 possible phenotypes for that; A-B-, A-bb, aaB-, and aabb, with a ratio of 9:3:3:1.

You can even have a trihybrid cross, where you cross AaBbCc x AaBbCc. That takes even longer to do, and you can have even more than that; I've seen a question with 6 different traits. By the time you reach a trihybrid cross, making a Punnett Square gets REALLY difficult and time-consuming, so there's a shortcut you can do. I posted it a few pages back, so read that if you want. If you can't find it, ask me and I'll type it out again.

I probably went into a lot more detail than you wanted, hehe, but I hope that helped.

thank u

[The Eviscerator]

Was it just me or did anybody else think the C division Designer Genes test was way too easy? Compounded with the fact that there were something like 4 questions where we needed a codon amino-acid chart and weren't provided with one, I feel like the scores must have been pretty close and kinda sketchy. I remember a lot of the teams finishing really, absurdly early and looking really worried.

[gneissisnice]

Was it just me or did anybody else think the C division Designer Genes test was way too easy? Compounded with the fact that there were something like 4 questions where we needed a codon amino-acid chart and weren't provided with one, I feel like the scores must have been pretty close and kinda sketchy. I remember a lot of the teams finishing really, absurdly early and looking really worried.

You were expected to memorize the amino acid codon chart? Wow, that's insane.