Zea Mays Mendelian Inheritance Pattern

Mendelian Genetics Rough Draft

Hypothesis I (Theory of Segregation)

At anaphase I of meiosis, gamete formation causes a separation of alleles in a diploid organism. When the chromosomes separate each individual will receive an equal chance of inheriting a dominant or recessive allele from the mother or father. Because an albino and green offspring were observed within the same generation, the parents must be heterozygous since two recessive alleles must be inherited by the offspring to express a recessive albino trait following Mendel's 3:1 (green: albino) ratio.

Hypothesis II (Theory of Independent Assortment)

During metaphase I of meiosis, the allele pairs of different genes will independently segregate from each other during the formation of gametes. The inheritance of an allele is independent of other pairs of alleles due to random alignment of chromosomes. Because there were two heterozygous plants for both height and color and were crossed, their offspring will follow Mendel's ratio of 9:3:3:1.

Materials & Methods

Obtaining and Maintaining Corn

To assess the inheritance patterns of Zea Mays (corn plants) that contain chlorophyll and no chlorophyll and whether the phenotype's height is normal or dwarf in green or albino plants, the study was conducted at Pacific Lutheran University's Carol Sheffels Quigg Greenhouse. The trays of corn plants were monitored under artificial lights, controlled temperature, and watered by a student worker for approximately two weeks.

Determining Green vs. Albino

Seven trays of monohybrid corn plants were observed, and the height and color were used to describe the plant's phenotype.

Determining Normal vs. Dwarf & Green vs. Albino

Five trays of dihybrid corn plants were observed to distinguish between green and albino from normal and dwarf. For the dihybrid cross, they were observed using the inheritance of two genes, color, and height. The normal green height plants are dominant presented themselves as tall, spread out, and leaves were narrower, whereas the albino normal height plants are recessive and were portrayed as thin, lack of chlorophyll, and were wrinkly. The green dwarf plants had chlorophyll and were shorter, whereas the albino dwarf plants displayed a wrinkled texture and brown leaves. If some of the corn plants displayed brown or died over the course, they were omitted from this experiment.

Data Analysis

Determining the phenotypic ratio of the dihybrid cross, of the normal green height as well as green-dwarf, albino-normal height, and albino-dwarf seedlings, their predicted frequencies were determined using a Punnet square to calculate the possible genotypes and albino offspring to be present. Once these were determined, they were computed to conclude the frequencies for the monohybrid and dihybrid cross through a Chi² test to get the expected and observed values.

Results

Table 1: Compares heterozygous seedlings that display the predicted number of green (G) and albino (W) when observing the phenotypic traits of chlorophyll and non-chlorophyll plants by Mendel's first law of Segregation, (N=424) Zea Mays.

The observed values were close to the phenotype prediction in the monohybrid cross, 75% displayed a dominant trait, and 25% a recessive trait. The expected and observed, (X²= 12, df = 1, p > 0.05), were not statistically significant.

Table 2: Compares the predicted and observed phenotypes of green normal and dwarf height and albino normal and dwarf height offspring phenotypes as predicted by Mendel's Theory of Independent Assortment to the number of observed phenotypes.

Observed traits of normal vs. dwarf green plants and albino plants, the phenotypic frequencies expected value did not follow Mendel's ratio of 9:3:3:1. The observed values, (X² = 53.5, df = 3, p < 0.05), is statistically different from the expected values.

Conclusions   

Our study supports the Mendelian inheritance pattern of Zea Mays that both the parent strains on the monohybrid cross (Table 1) were heterozygous. The expected and observed, (X²= 12, df = 1, p > 0.05), were statistically significant with Mendel's first law of segregation expressing green or albino following the phenotype ratio of 3:1. Whereas, the parent strains on the dihybrid cross (Table 2) the observed values for the albino normal and albino dwarf (X² = 53.5, df = 3, p < 0.05), were statistically different from the expected and observed values. Therefore, refuting Mendel's Law of Independent Assortment. The difference between the observed and expected data could be due to human error, omitting the dead albino plants, and or a small sample size.