Hardy-Weinberg Lab
Laboratory 7, AP Biology
Abstract
Through the random mating simulation completed in lab one (the rabbit lab) we were able to see how within nature lethal genes often are passed through a population of animals. In this case, the recessive gene for no hair, which in turn disabled the rabbits to withstand the harsh climates thus killing them. Though this simulation was not in perfect ‘Hardy-Weinberg equilibrium’, it gave us a more accurate reading of how traits are passed down in a non-perfect setting, ones that mirror real life more accurately. The overarching concept was to be able to understand trait inheritance and being introduced to calculating expected allele outcomes within a given population using the ‘Hardy-Weinberg’ equations.
Introduction
In this lab we will be modeling Hardy Weinberg’s law of genetic equilibrium. This law proposes that the frequency of alleles and genotypes in a population will remain constant from generation to generation if the population is stable and in genetic equilibrium. This would mean that in order for the population to remain the conditions required would be: a large breeding population, random mating, no change in allelic frequency, no immigration or emigration, and no natural selection.
We will run random mating simulations by using red and white beads to represent the alleles in a rabbit population. A group member will blindly select two beads that will then be paired together. This lab will be selected against recessive alleles ff. (two white beads)
Methods
This study was conducted in the biology classroom at New Tech. The lab was conducted in the effort to simulate generations of a bunny population. In order to simulate the alleles of a bunny population we used red and white beads. The red beads symbolized the dominant gene while the white beads symbolized the recessive gene. A homozygous dominant (2 reds) and a heterozygous (1 red, 1 white) allowed for the offspring to survive. However, if the offspring were to be homozygous recessive (2 whites) it would not be able to survive. There were no other genotypes we experimented for in this lab other than the lethal allele for no hair.
We placed the beads in a bowl and randomly selected 2 beads without looking. After selecting all the beads we eliminated the homozygous recessive alleles and removed them from the sample size. Then we conducted the trial again with the remaining beads. We continued this process for 10 trials.
In the second part of the lab, we introduced a mutation into the sample size. This mutation was a lethal recessive allele, which coded for blue fur. Each time this allele appeared paired with another recessive allele we removed it from the population. We conducted this for 5 trials.
Results
Overall, our data in the 1st lab showed that throughout the generations the total number of alleles slowly decreased. The gene frequency of dominant alleles drastically increased from 50% to 96% over the past ten generations. Opposite to the dominant alleles, the gene frequency of recessive alleles drastically decreased over the generations from 50% to 4%.
Discussion
The findings in this study display the results of a population over several generations while not in perfect ‘Hardy-Weinberg Equilibrium”. The lab suggests that over several generations the lethal allele will eventually die out of the population. The homozygous recessive offspring will die and the heterozygous carriers will pass down their traits to the next generation but will not die because only the dominant allele will be expressed. Once the hairless offspring numbers begin to dwindle it becomes less likely to produce more hairless offspring. However, in the process of the lethal allele dying out the numbers of the entire population have diminished.
The data for a lethal mutation being introduced into the population is similar. Any time the mutation appeared with another recessive allele the offspring would not be able to survive. If the mutation appeared with the dominant allele than the offspring would simply be a carrier of the trait.
The lab gave us the opportunity to simulate the effects of heredity in a bunny population. Possible causes of error include, miscounting, the offspring not truly being random, and the absence of outside factors other than lethal alleles in the population.
Conclusion
As stated before, this lab had used a sampling that was considerably not in ‘Hardy-Weinberg’ conditions. Had it been in such condition we would have had much larger numbers and none of the rabbits would have died due to a genetic ailment. After “mating” the rabbits 9 different times to produce genetically different offspring we saw that: either the genetic ailment would kill off the entire rabbit population, or the majority of the rabbit population would continue to survive and just the ones with the ailment would die off. Our results for our specific population showed that through different periods in time, the population would be stable if the recessive gene containing the ailment wasn’t expressed. Instability would only occur whenever the gene was actually being expressed, thus killing the rabbit due to insufficient fur. The periods that were considerably stable were due to the fact that although some rabbits did have the allele it wasn't heterozygously expressed thus alluding to a stable population. Permanent stability was only achieved once all rabbits containing the recessive allele died off so that no other rabbits could inherit furlessness.
Works Cited
Chowdhury, Rodriguez, Ruiz.(2014). Hardy-Weinberg Student Input.
Reece, C. (2014). AP Biology. Pearson.
Wootton, K. (2014). Hardy-Weinberg Lab Notes. Coppell: Wootton, Kim.
Charts:
Laboratory 7, AP Biology
Abstract
Through the random mating simulation completed in lab one (the rabbit lab) we were able to see how within nature lethal genes often are passed through a population of animals. In this case, the recessive gene for no hair, which in turn disabled the rabbits to withstand the harsh climates thus killing them. Though this simulation was not in perfect ‘Hardy-Weinberg equilibrium’, it gave us a more accurate reading of how traits are passed down in a non-perfect setting, ones that mirror real life more accurately. The overarching concept was to be able to understand trait inheritance and being introduced to calculating expected allele outcomes within a given population using the ‘Hardy-Weinberg’ equations.
Introduction
In this lab we will be modeling Hardy Weinberg’s law of genetic equilibrium. This law proposes that the frequency of alleles and genotypes in a population will remain constant from generation to generation if the population is stable and in genetic equilibrium. This would mean that in order for the population to remain the conditions required would be: a large breeding population, random mating, no change in allelic frequency, no immigration or emigration, and no natural selection.
We will run random mating simulations by using red and white beads to represent the alleles in a rabbit population. A group member will blindly select two beads that will then be paired together. This lab will be selected against recessive alleles ff. (two white beads)
Methods
This study was conducted in the biology classroom at New Tech. The lab was conducted in the effort to simulate generations of a bunny population. In order to simulate the alleles of a bunny population we used red and white beads. The red beads symbolized the dominant gene while the white beads symbolized the recessive gene. A homozygous dominant (2 reds) and a heterozygous (1 red, 1 white) allowed for the offspring to survive. However, if the offspring were to be homozygous recessive (2 whites) it would not be able to survive. There were no other genotypes we experimented for in this lab other than the lethal allele for no hair.
We placed the beads in a bowl and randomly selected 2 beads without looking. After selecting all the beads we eliminated the homozygous recessive alleles and removed them from the sample size. Then we conducted the trial again with the remaining beads. We continued this process for 10 trials.
In the second part of the lab, we introduced a mutation into the sample size. This mutation was a lethal recessive allele, which coded for blue fur. Each time this allele appeared paired with another recessive allele we removed it from the population. We conducted this for 5 trials.
Results
Overall, our data in the 1st lab showed that throughout the generations the total number of alleles slowly decreased. The gene frequency of dominant alleles drastically increased from 50% to 96% over the past ten generations. Opposite to the dominant alleles, the gene frequency of recessive alleles drastically decreased over the generations from 50% to 4%.
Discussion
The findings in this study display the results of a population over several generations while not in perfect ‘Hardy-Weinberg Equilibrium”. The lab suggests that over several generations the lethal allele will eventually die out of the population. The homozygous recessive offspring will die and the heterozygous carriers will pass down their traits to the next generation but will not die because only the dominant allele will be expressed. Once the hairless offspring numbers begin to dwindle it becomes less likely to produce more hairless offspring. However, in the process of the lethal allele dying out the numbers of the entire population have diminished.
The data for a lethal mutation being introduced into the population is similar. Any time the mutation appeared with another recessive allele the offspring would not be able to survive. If the mutation appeared with the dominant allele than the offspring would simply be a carrier of the trait.
The lab gave us the opportunity to simulate the effects of heredity in a bunny population. Possible causes of error include, miscounting, the offspring not truly being random, and the absence of outside factors other than lethal alleles in the population.
Conclusion
As stated before, this lab had used a sampling that was considerably not in ‘Hardy-Weinberg’ conditions. Had it been in such condition we would have had much larger numbers and none of the rabbits would have died due to a genetic ailment. After “mating” the rabbits 9 different times to produce genetically different offspring we saw that: either the genetic ailment would kill off the entire rabbit population, or the majority of the rabbit population would continue to survive and just the ones with the ailment would die off. Our results for our specific population showed that through different periods in time, the population would be stable if the recessive gene containing the ailment wasn’t expressed. Instability would only occur whenever the gene was actually being expressed, thus killing the rabbit due to insufficient fur. The periods that were considerably stable were due to the fact that although some rabbits did have the allele it wasn't heterozygously expressed thus alluding to a stable population. Permanent stability was only achieved once all rabbits containing the recessive allele died off so that no other rabbits could inherit furlessness.
Works Cited
Chowdhury, Rodriguez, Ruiz.(2014). Hardy-Weinberg Student Input.
Reece, C. (2014). AP Biology. Pearson.
Wootton, K. (2014). Hardy-Weinberg Lab Notes. Coppell: Wootton, Kim.
Charts: