Sunday, March 11, 2012

Lab - Genetic Crosses

Punit Squares
Guiding Question:
How can you predict the possible results of genetic crosses?
Hypothesis: Throught the Punit squares, it is usually
Data Table 1:
TrialAllele From Bag 1 (Female Parent)Allele From Bag 2 (Male Parent)Offsprings Alleles
1BbBb
2BbBb
3BbBb
4BbBb
5BbBb
6BbBb
7BbBb
8BbBb
9BbBb
10BbBb


Data Table 2:
TrialAllele From Bag 1 (Female Parent)Allele From Bag 2 (Male Parent)Offsprings Alleles
1BBBB
2BbBb
3BBBB
4BbBb
5BbBb
6BBBB
7BbBb
8BbBb
9BbBb
10BBBB


Data Table 3:
TrialAllele From Bag 1 (Female Parent)Allele From Bag 2 (Male Parent)Offsprings Alleles
1BbBb
2BBBB
3BbBb
4BbBb
5BBBB
6bBbB
7BBBB
8BbBb
9bBbB
10BbBb


Analyzing Data:
Step 1 Punnet Squares:
2 Homozygous ParentsBB
bBbBb
bBbBb


Heterozygous & Homozygous ParentsBB
BBBBB
BBbBb


Heterozygous ParentsBb
BBBBb
bBbbb


Step 2:
According to your results in Part 1, how many diffrent kinds of offspring are possible when the homozygous parents(BB and bb) are crossed? Do the results you obtained using the marble model agree with the results shown by a Punnett square?

In each of our tables and tests we scored the exact same precent of getting the same offspring in alleles. In the first table there is 100% of getting a Bb offspring, but also in our punnent squares the final product was 100% me and my partner agree that this proves that in this case the punnet square method is correct.

Step 3:
According to your results in Part 2, what percentage of offspring are likely to be homozygous when a homozygous parent (BB) and a heterozygous parent (Bb) are crossed? What percentage of offspring are likely to be heterozygous? Does the model agree with the results shown by a Punnett square?

In the second graph that me and my partner recorded we ran into a bit of trouble, acourding to our table we got 4 BB out of 10 tries which means we had 40% chance of getting BB offspring the problem was that according to our punnet squares their should be 50% chance of getting BB offspring. The reason this happened is that the punnet squares are statistics but nature is chance, when we made the table we picked out of a bag therefor that is chance, but the punnet square has to be one answer, even though we only got 4/10 BB  it is very close to 50% which still proves that the punnet method is fairly reliable.

Step 4:
According to your results in Part 3, what diffrent kinds of offspring are possible when two heterozygous parents (BbxBb) are crossed? What percentage of each type of offspring are likely to be produced? Does the model agree with the results of a Punnett square?

In this last data table again we pulled out of a bag, which again gives us chance of anything happening, and as we guessed it, something did according to statistics or the punnet squares there should be a 50% chance of getting the Bb, 25% chance for getting an offspring BB, and a 25% chance of getting an offspring of bb, but because of life's chance we got 80% of the Bb offspring and 20% chance of getting the BB offspring, this is again because of life, but it does show that the punnet square was close and is reliable.

Step 5:
For Part 3, if you did 100 trails instead of 10 trails, would your results be closer to the results shown in a punnett square? Explain.

You can never know for sure if the results can be the same because of chance, but you can know for sure that trying it 100 is a lot more reliable and secure than it would be if you only took 10 tests, obviously because of this you would have more Data and statistics.

Step 6:
In a paragraph, explain how the marble model compares with a Punnett square. How are the two methods alike? How are they different?

Both methods are extremely simulare and both of them represents the probability for an offspring, and a inheritance trait from parents. Even though this is true, there are some major differences, for example the punnet squares the probability of a genotype, and represents the percentage of getting a certain trait, against the marble method which shows a real life example and provides chance.

1 comment:

  1. Your tables and Punnett squares were very well marked and showed your data in an organized fashion. Great job in this. You also analyzed your data well in discussing the data from the marbles as well as how they compare to the Punnett square probabilities that you got in the end. Good work!

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