StudentShare
Contact Us
Sign In / Sign Up for FREE
Search
Go to advanced search...
Free

Dihybrid Cross and Chi Square - Thesis Example

Cite this document
Summary
G.J. Mendel’s plant breeding experiments provided proof for such hereditary patterns. Mendel’s experiments with peas helped him define…
Download full paper File format: .doc, available for editing
GRAB THE BEST PAPER92.5% of users find it useful
Dihybrid Cross and Chi Square
Read Text Preview

Extract of sample "Dihybrid Cross and Chi Square"

The paper "Dihybrid Cross and Chi-Square" is an excellent example of a lab report on biology. One of the most fascinating properties of a living cell is its ability to transfer its hereditary properties from one generation to another. G.J. Mendel’s plant-breeding experiments provided proof for such hereditary patterns. Mendel’s experiments with peas helped him define three basic laws of inheritance known as Mendel’s Laws of Inheritance. The first principle deals with the hereditary characters i.e. passing of genes from parents to off-springs.

The second principle or principle of Segregation states that during breeding the inheriting factors or alleles segregate into the reproductive cells and unite randomly during fertilization. The third principle also is known as the Law of Independent Assortment states that genes located on different chromosomes will be inherited independently. Thus, it is today established that each trait is controlled by variations of a single gene. These two variants are referred to as alleles- one is derived from each parent.

These controlling genes are responsible for variations in both phenotypic and genotypic makeup, where phenotypic makeup refers to the physical appearance of the offspring (e.g. Green pea) and the genotypic makeup refers to the genetic composition (e.g. Gg for green pea). Again, the genotypic makeup depends on the type of allele present. If an individual has two copies of the same allele they are known as homozygous (e.g. RR, rr ) while an individual with two different copies of the same allele is referred to as heterozygous (e.g. Rr) (Watson et al, 2004).

In some cases, the dominant nature of a gene may be both homozygous and heterozygous. Homozygous dominant refers to the gene which is dominant in its homozygous form while heterogous dominance is the state of a gene when the gene expresses in its heterozygous form. A Punnett Square is a representation of the phenotypes and genotypes in a tabular form and gives a much simple representation of possible off-springs from the parental gametes. Within a population, some phenotypes are more common than others owing to their dominant feature and their success in establishing themselves in the population.

In fact, variation occurs in all living organisms including plants. Corn also shows variations in the form of colors. Corn kernels may be yellow or purple. In this lab, a dihybrid cross is performed between two different corns having different genotype and phenotypes and investigate if they follow Mendel’s principles. Hypotheses- In the dihybrid study where the heterozygous F1 generation of purple starchy (P/p S/s) is crossed the ratio of the resultant off-springs will be 9:3:3:1 (56% purple & starchy, 19% purple & sweet, 19% yellow & starch and 6% yellow & sweet).

Method In this laboratory, the dihybrid cross between purple starchy (P/P S/S) and yellow sweet ( p/p s/s) was studied. The phenotype of the offsprings was then recorded by working in pairs and marking and counting the grains. The values were recorded in the table below (Table 1). The Chi-square test is used to compare the observed and the expected data and analyze the extent to which they differ using the probability of p=0.1. Results The observed and expected values are tabulated. We see that Purple/sweet numbers obtained are a mere 73 whereas its expected value is 257.63. Also, in the case of yellow/sweet the observed value is 297 which is much higher than the expected value of 85.88. The ratio of the observed is very much different from the expected ratio of 9:3:3:1.

However to analyze the degree to which the ratios differ we employ the chi-square test with a degree of freedom=3, however the deviation too large to obtain data. From the given table of Chi-square, the value cannot be determined. Discussion The chi-square value that we get is extremely high. In fact, the purple-sweet phenotype is observed much below the expected value while yellow-sweet phenotype is extremely high than the expected value and therefore the hypothesis cannot be true. From the results, it can be said that sweet is recessive but the recessive nature of yellow cannot be determined.

We can reject the hypothesis owing to jumping genes or transposons which cause color disruption in corn. It was owing to these jumping genes that some corns were not completely yellow in color. Transposons do not comply with Mendel’s principles. Conclusion This experiment investigates and establishes that existence of transposons has the potential to change both genotype and phenotype and thus the expected ration of 9:3:3:1 in a dihybrid cross is not always obtained.

Read More
Cite this document
  • APA
  • MLA
  • CHICAGO
(Dihybrid Cross and Chi Square Thesis Example | Topics and Well Written Essays - 500 words - 10, n.d.)
Dihybrid Cross and Chi Square Thesis Example | Topics and Well Written Essays - 500 words - 10. https://studentshare.org/biology/1880218-lab-report
(Dihybrid Cross and Chi Square Thesis Example | Topics and Well Written Essays - 500 Words - 10)
Dihybrid Cross and Chi Square Thesis Example | Topics and Well Written Essays - 500 Words - 10. https://studentshare.org/biology/1880218-lab-report.
“Dihybrid Cross and Chi Square Thesis Example | Topics and Well Written Essays - 500 Words - 10”. https://studentshare.org/biology/1880218-lab-report.
  • Cited: 0 times

CHECK THESE SAMPLES OF Dihybrid Cross and Chi Square

Quantitative Techniques ( use Eviews and Excel )

001 Chi-square 20.... Chi-square(3) 0.... Chi-square(3) 0.... Chi-square(9) 0.... Chi-square(9) 0.... Chi-square(4) 0.... 000 Chi-square 21.... Table 16 Dependent Variable: INVESTMENT Method: Panel Least Squares Date: 12/31/11 Time: 15:18 Sample: 1998 2006 Periods included: 9 cross-sections included: 1017 Total panel (unbalanced) observations: 7325 Coefficient Std....
6 Pages (1500 words) Essay

Lin-Chi and the Ten Feet Square Hut

NAME OF THE STUDENT: LIN-CHI AND THE TEN FEET square HUT THE ZEN TEACHINGS OF THE MASTER LIN-CHI Record of Lin-chi, translated by Burton Watson explains the existence of a true man without rank in an explicit manner.... Inspiring sayings of Leader of Zen Master, Lin- chi concluded complex laws of life and success; in an easy approach.... Lin-chi the master of martial arts depicted action in equilibrium and the tone of voice adjacent to the action....
5 Pages (1250 words) Essay

Square Electronic Payment Service Analysis

Date square is an electronic payment service that is offered by the square incorporation in the US.... When Apple becomes the first to adopt this platform, it means square will lose a lot of clients most so the technology oriented who are the majority in the current market place where convenience is the key determinant (Glover, Stephen and Douglas).... The second need for square Inc to adopt an e business platform is to enable it to extend into the non-US markets and this has to happen at the fastest rates....
4 Pages (1000 words) Essay

GENETICS EXPERIMENTS FLYLAB

-------------------------------------------------------------------------- chi square Hypothesis Using Cross #2 Phenotype Observed Hypothesis Expected Chi-Square Term Female: + 3697 1.... -------------------------------------------------------------------------- chi square Hypothesis Using Cross #2 Phenotype Observed Hypothesis Expected Chi-Square Term Female: + 3697 3.... -------------------------------------------------------------------------- chi square Hypothesis Using Cross #3 (F1 Generation) Phenotype Observed Hypothesis Expected Chi-Square Term Female: + 501 1....
3 Pages (750 words) Essay

T-Test and Chi-Test

A paper "T-Test and chi-Test" claims that the first hypothesis is expected that the mean of tenures between 1 and 2 will be similar.... nbsp;From the result of the degrees of freedom, we can analyze that the null hypothesis is unacceptable T-Test and chi-TestUnit 3 In the T-Test, the first hypothesis is expected that the mean of tenures between 1 and 2 will be similar.... hellip; In the Chi-square Test, we compared the expected and observed frequencies of the particular data set....
2 Pages (500 words) Assignment

The T Test and the Chi-square Test

he chi-square test is used to compare the observed data with data expected to obtain according to a specific hypothesis.... Thus chi-square test statistic is designed to test the null hypothesis that there is no association between the rows and columns.... This discussion talks that the t-distribution can be used to compare the mean of a sampled population to some fixed, known value....
5 Pages (1250 words) Article

Mate choice & plumage polymorphism in the feral pigeon (Columba livia)

Aim of this paper is to evaluate the association of plumage polymorphism and mate choice in feral pigeons using Chi-square test.... The research on feral pigeons plumage based mating is carried as described in academic handbook using Chi-square test of independence.... Chi-square test of independence tests the association between two definite variables.... The result (χ2) is then looked up on a Chi-square (χ2) table with a number of degrees of freedom (df)....
4 Pages (1000 words) Essay

Lin-Chi and the Ten Feet Square Hut

This paper ''Lin-Chi and the Ten Feet square Hut'' tells that Record of Lin-chi, translated by Burton Watson explains the existence of a true man without rank in an explicit manner.... nspiring sayings of Leader of Zen Master, Lin- chi concluded complex laws of life and success; in an easy approach.... in-chi the master of martial arts depicted action in equilibrium and the tone of voice adjacent to the action....
5 Pages (1250 words) Essay
sponsored ads
We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.
Contact Us