Mendelian genetics, created by Gregor Mendel in the 1800s, helps us understand how traits are passed down from parents to their children. It centers around two important ideas: genotype and phenotype.
Genotype vs. Phenotype
Genotype: This means the genetic makeup of a person or plant. It tells us about the specific forms of genes they have. For example, in pea plants, the gene for tall plants is represented by T, and the gene for short plants is t. A plant with the genotype TT or Tt will be tall.
Phenotype: This is what we can see or observe about an organism, like its appearance or other traits. This is influenced by both the genotype and the environment. So, both TT and Tt plants will look tall (their phenotype), while a plant with the genotype tt will be short.
Mendelian Principles
Mendel came up with some important rules about how traits are passed down. Two main rules are:
Law of Segregation: This rule says that when sperm and egg cells are made, the two gene forms (alleles) for a trait separate from each other. For example, a plant with the genotype Tt can create two types of gametes: one with T and one with t.
Law of Independent Assortment: This rule means that the way one trait is inherited usually doesn’t affect how another trait is inherited. For instance, if we look at two traits, like plant height (T/t) and flower color (R/r), the combinations of these traits in the gametes can create different mixes, like TR, Tr, tR, and tr.
Using Punnett Squares
Punnett squares are a helpful way to predict the genotype and phenotype of offspring from their parents. For example, if we cross a tall plant that has the genotype TT with a tall plant that has the genotype Tt, a Punnett square will show:
So, all the offspring will be tall. This shows how Mendelian principles help us understand the connection between genotype and phenotype in a simple way!
Mendelian genetics, created by Gregor Mendel in the 1800s, helps us understand how traits are passed down from parents to their children. It centers around two important ideas: genotype and phenotype.
Genotype vs. Phenotype
Genotype: This means the genetic makeup of a person or plant. It tells us about the specific forms of genes they have. For example, in pea plants, the gene for tall plants is represented by T, and the gene for short plants is t. A plant with the genotype TT or Tt will be tall.
Phenotype: This is what we can see or observe about an organism, like its appearance or other traits. This is influenced by both the genotype and the environment. So, both TT and Tt plants will look tall (their phenotype), while a plant with the genotype tt will be short.
Mendelian Principles
Mendel came up with some important rules about how traits are passed down. Two main rules are:
Law of Segregation: This rule says that when sperm and egg cells are made, the two gene forms (alleles) for a trait separate from each other. For example, a plant with the genotype Tt can create two types of gametes: one with T and one with t.
Law of Independent Assortment: This rule means that the way one trait is inherited usually doesn’t affect how another trait is inherited. For instance, if we look at two traits, like plant height (T/t) and flower color (R/r), the combinations of these traits in the gametes can create different mixes, like TR, Tr, tR, and tr.
Using Punnett Squares
Punnett squares are a helpful way to predict the genotype and phenotype of offspring from their parents. For example, if we cross a tall plant that has the genotype TT with a tall plant that has the genotype Tt, a Punnett square will show:
So, all the offspring will be tall. This shows how Mendelian principles help us understand the connection between genotype and phenotype in a simple way!