Dominant and Recessive alleles

[Sora]

I have an exam on wednesday about genes, punnett squares, gene maps, etc.
I have trouble understanding Independent Assorment, Incomplete Dominance, Codominance, Multiple Alleles, and Polygenic traits.

Also, for punnett squares, I'm still not clear on genotypic ratios and phenotypic ratios.
What is the difference between them?

This is the punnett square from my practice questions:
B b
B BB Bb

b Bb bb

My guess is that the genotypic ratio is 1:2:1 and ..I'm not so sure about the phenotypic ratio.

[lozerface16]

ugh i have the same issue!!!!
but i have to find the possible phenotype of the offspring in a proportion!
it is all so confusing pleh...

[smalik]

Lets say the trait is Attached ears or Free ears. Where Free(B) is dominant, and (b) is reccesive.

The phenotype ratio is 1 carrier: 2 dominant: 1 recessive.

[Sora]

ugh i have the same issue!!!!
but i have to find the possible phenotype of the offspring in a proportion!
it is all so confusing pleh...

yeah, I know.
I wish I could help, but I don't know myself either.

[Sora]

Lets say the trait is Attached ears or Free ears. Where Free(B) is dominant, and (b) is reccesive.

The phenotype ratio is 1 carrier: 2 dominant: 1 recessive.

Oh, okay
I think I get it a little better now..thanks

So, the 2 dominant is the BB, Bb, Bb
and the recessive is bb?

[lozerface16]

ugh i am so going to fail this test...............

[Sora]

:evil: ugh i am so going to fail this test...............

\
aww
When is your test?
Tomorrow?

[cracked_doc]

So, the 2 dominant is the BB, Bb, Bb
and the recessive is bb?

the genotypic ratio will be : 1:2:1 as in 1 dominant (BB): 2 carriers (Bb): 1 recessive (bb)

BB is called dominant homozygous as it has both the dominant alleles for a character
Bb will also show same phenotype as BB but its called heterozygous as the two alleles are different

both will show the phenotype B

bb on the other hand will have phenotype b (for whatever traits you are discussing)

[lozerface16]

:evil: ugh i am so going to fail this test...............

\
aww
When is your test?
Tomorrow?

yeah it was today.......
i hope i did at least decent on it....

[Sora]

So, the 2 dominant is the BB, Bb, Bb
and the recessive is bb?

the genotypic ratio will be : 1:2:1 as in 1 dominant (BB): 2 carriers (Bb): 1 recessive (bb)

BB is called dominant homozygous as it has both the dominant alleles for a character
Bb will also show same phenotype as BB but its called heterozygous as the two alleles are different

both will show the phenotype B

bb on the other hand will have phenotype b (for whatever traits you are discussing)

Oh, thank you for explaining.

[Sora]

:evil: ugh i am so going to fail this test...............

\
aww
When is your test?
Tomorrow?

yeah it was today.......
i hope i did at least decent on it....

Oh, I'm sure you did well.
As long as you tried your best.

[lozerface16]

aww
When is your test?
Tomorrow?[/quote]

yeah it was today.......
i hope i did at least decent on it.... [/quote]



Oh, I'm sure you did well.
As long as you tried your best. [/quote]


lol i took the whole class period
i better have done well
i will find out tomorrow!!