Dominant and Recessive genes
People contain 23 pairs of chromosomes and their genes are from their mom and dad. In meiosis, the human cells carry two copies of each chromosome, which has two versions. The different versions called alleles can be either dominant and recessive. When the two alleles interact and combine, they become a Homozygous (either dominant and recessive) or Heterozygous.
Homozygous describes the genetic state when an individual has inherited the same DNA sequences for a particular gene, such as dominant traits and recessive traits from their biological parents. Homozygous has two different types: Homozygous dominant and Homozygous recessive. Two dominant alleles create Homozygous dominant and two recessive alleles create homozygous recessive. Recessive alleles can exist and appear when they are Homozygous recessive.Â
On the other hand, Heterozygous describes the genetic state when an individual has inherited two different DNA sequences that contain both dominant trait and recessive trait. Although Heterozygous has dominant and recessive traits, Heterozygous always has a dominant characteristic.
What determines the traits of genes
Specific versions of genes appear for lots of different reasons. The simplest and the most general situation of determining dominant traits and recessive traits is when one allele makes a broken protein; All of the alleles, created by biological parents, have the purpose of producing proteins. In this situation, the working protein becomes a dominant gene, and the broken protein becomes a recessive gene. Since broken protein lost its power to perform the roles, the working protein (dominant) wins over the broken protein (recessive)
Gregor Mendel’s Pea Experiment
Gregor Mendel, the father of Genetics, left the scientific legacy in the genetic field. He studied the heredity of the organisms. Although he began his study with rats, honey bees, he ultimately used the features of peas. Gregor Mendel separated each category, including height, flower color, seed color, and seed shape.Â
In Mendel’s experiment of pea’s height, he pollinated two different types of pea features: a tall pea tree and a short pea tree. When he cultivated offspring of two pea trees, All of the offspring were tall. Subsequently, the tall trees self-fertilized, producing tall trees and short trees simultaneously with 3 (tall trees): 1 (short trees) ratio.Â
The evidence from Medel’s experiment can elicit that the first generation of a tall tree and a short tree contain Homozygous traits. Moreover, the second generation (the offspring of the first generation trees) show Heterozygous and dominant traits using the evidence: all of the trees were tall. Although Mendel cultivated the offspring from both the short trees and the tall trees, all of the offspring show the tall traits. The result can conclude that the tall height trait is the dominant gene, and the short height trait is the recessive gene.
 Furthermore, when Heterozygous features were self-fertilized, It produced three tall trees: one short tree. According to the picture, two Heterozygous features pollination produce one Homozygous dominant, two Heterozygous, and one Homozygous recessive. Therefore, Homozygous dominant and Heterozygous produce the tall trees, and only Homozygous recessive produce the short trees with ratio 3: 1.Â
Dominant and Recessive Chart
BibliographyÂ
Difference between dominant and recessive alleles [Digital image]. (n.d.). Retrieved July 29, 2020, from https://www.differencebetween.com/wp-content/uploads/2013/03/Difference-Between-Dominant-and-Recessive-Allele_Figure-1-e1557305549763.jpg
Kaplan, R. (2016, September 19). Dear Science: Why are some genes dominant and some genes recessive? Retrieved July 29, 2020, from https://www.washingtonpost.com/news/speaking-of-science/wp/2016/09/19/dear-science-what-are-some-genes-dominant-and-some-genes-recessive/
These Punnett Squares show the various outcomes of homozygous [Digital image]. (n.d.). Retrieved July 29, 2020, from https://i.pinimg.com/originals/53/df/ba/53dfba76b1b0b0fe11db07762efd56cc.png
What are dominant and recessive alleles? (2016, January 25). Retrieved July 29, 2020, from https://www.yourgenome.org/facts/what-are-dominant-and-recessive-alleles
(n.d.). Retrieved July 29, 2020, from https://genetics.thetech.org/ask/ask227