Please help me understand the punett square!?

The Punnett Square is basically just a way to visualize the relative probabilities of certain genetic and phenotypic results from two organisms mating. The site below has excellent examples of various squares.

okay so the punett square basically allows you to see every possible combination of the alleles and the their frequency e and probability.

lets say you have two individuals which are TT and tt

the TT are homozygous dominant for being tall

and the tt are homozygous recessive for being short

Tt is the heterozygous version in which T is dominant so these individuals will also be tall.

so to find your possible outcomes if Tt and Tt mate would be

-----T-------t

T---TT-----Tt

t----Tt-------tt

so as you can the top Tt is for one individual mating and the left Tt is for the other individual. So from this we can see that 1/4 would be TT (homozygous dominant), 2/4 = 1/2 would be Tt (heterozygous), and 1/4 will be tt (heterozygous recessive).

Also 3/4 will be tall (TT and Tt will both yield a tall phenotype) and 1/4 will be short (tt will yield a short phenotype)

Phenotype is the physical characteristic so TT and Tt have the same physical characteristic but tt doesn't.

Genotype is the genetic characteristic so TT, Tt, and tt do not have the same genetic characteristic.

Blood is somewhat diverse than customary genotypes. the position you oftentimes have a huge letter and somewhat letter, in blood you've 2 huge letters and a diverse little letter. it fairly works like this: O blood has the genotype oo A blood ought to correctly be both Ao or AA B ought to correctly be Bo or BB AB is often AB that is because the o is recessive and the A and B are dominant. i'd have purely defined some thing you recognize. the mummy determine with form A blood does not have both Ao and AA genotypes, she ought to in ordinary words have definitely a spread of genotypes. yet in case you do not understand which one she has, you'll ought to definitely make 2 Punnet squares, one in which she has Ao and one in which she had AA, to determine out the a danger blood sorts of the newborn.

Just draw a box like so:

A a B b

A

a

B

b

(Using whichever alleles you are given.)

Then fill in the blanks -- dominant genes are phenotypically expressed over recessive genes -- which means that Aa receives the "A" trait, not the "a" trait.

punnet squares arent hard to understand, all yuo have to do is split up each individual trait, and list every combination between the two types. Once your done that, find out which gene is dominant, and list the results.

You just look for what you need on the top and on the side. Go across and down and where they meet, thats what you need. Likeee.

A a

a Aa aa

A AA Aa

I guess thats kind of a bad explanation but..

its used for helping determine the chances offspring will have of receiving a certain trait. the mother's alleles for the trait (example hh for recessive gene) appear on one side. the father's alleles (example HH for completely dominant) appear on the other side. you then match them up, so each box would have Hh in it. this way, you know that all of the offsrping will have the dominant trait but be carriers for the recessive trait. You could then continue it. it's really quite simple. hope this helps.

its really easy, say u have AA and Aa....just multiply: A*A, A*a,A*A and Aa which gives u AA, Aa,AA and Aa. Just do it systematically multiply the first letter of the first thing by the first letter of the second thing and then the second letter of the second thing ect. LOL its really hard explaining over yahoo, o well i tried:D

Have a look here. A picture is worth a thousand words.

http://www.usoe.k12.ut.us/CURR/Science/sciber00/7t...