Inheritance with Punnett Squares lab report write up sample
Introduction:
Inheritance is the process by which genetic information is passed down from parents to offspring. One of the most common ways this occurs is through the process of meiosis, which is the formation of gametes (sperm and eggs) that carry half of the genetic information of their parent. Punnett squares are a useful tool that can be used to predict the probability of inheritance patterns based on the alleles (different versions of genes) present in the parent organisms. In this lab, we will use Punnett squares to investigate the inheritance of traits in pea plants.
Methods:
We were given two pea plants, one with yellow seeds (YY) and one with green seeds (yy). We crossed these plants and observed the resulting offspring. To predict the probability of offspring inheritances, we used Punnett squares. For example, to determine the probability of offspring with yellow seeds, we crossed a homozygous yellow seed (YY) pea plant with a homozygous green seed (yy) pea plant. The Punnett square showed that the probability of offspring with yellow seeds was 100%.
Results:
Our results showed that the Punnett squares accurately predicted the probability of inheritance patterns. When we crossed a homozygous yellow seed pea plant (YY) with a homozygous green seed pea plant (yy), all of the resulting offspring had yellow seeds (Yy). This is because the offspring inherit one Y allele from the yellow seed parent and one y allele from the green seed parent. Yellow seeds are dominant over green seeds, so the Y allele dominates and expresses the yellow seed trait.
When we crossed a heterozygous yellow seed pea plant (Yy) with a homozygous green seed pea plant (yy), some of the resulting offspring had green seeds (yy) and some had yellow seeds (Yy). The Punnett square predicted that the probability of offspring with green seeds was 50% and the probability of offspring with yellow seeds was 50%. This is because the heterozygous yellow seed parent can pass on either a Y or y allele to its offspring.
Discussion:
This lab demonstrates how Punnett squares can be used to predict the probability of inheritance patterns. By understanding the principles of dominant and recessive alleles and how they are passed down from parent to offspring, we can accurately predict the traits that will be expressed in future generations. This knowledge is important both for understanding basic genetics and for practical applications such as plant and animal breeding.