What is Genetics? A Brief Review.. Greetings

Understanding Genetics

The study of how traits are passed on from one organism to it’s offspring. Each cell has chromosomes in the nucleus. Chromosomes contain DNA, which determine the genetic make-up of an organism.

Chromosomes

The Father of Genetics Gregor Mendel Monk-liked pea plants Bored with religion Cross pollinated pea plants Tall = dominant (T) Short = recessive (t) Dominant more powerful than recessive Peas

Trait Expression DominantDominant Stronger trait Stronger trait Seen most often Seen most often Demonstrated with a CAPITAL letter Demonstrated with a CAPITAL letter Expressed if present with a recessive gene Expressed if present with a recessive gene Recessive Weaker trait Seen less often Demonstrated with a lower case letter Not expressed if present with a dominant gene, but not lost….

Homo/Heterozygous Traits Homozygous Purebred Can be dominant or recessive Both genes are the same TT or tt Heterozygous Hybrid (mutt) One dominant gene, one recessive gene Both genes are different Tt

Heterozygous and Homozygous

Genotype and Phenotype Genotype The genetic makeup of an organism For example  TT  Tt  tt Phenotype The outward expression of a gene For example  Tall or short  Brown or blue eyes  Straight or curly hair

Genotype and Phenotype

Incomplete Dominance o Neither is stronger than the other o Offspring is blended, a combination between both traits o For instance, red flower mated with white flower = pink

Punnett Square Movie

Punnett Squares Tall = (TT) X Short (tt) t t Tt T

Punnett Squares Tall = (Tt) X tall (Tt) T t TT Tt tt T t

Punnett Squares Tall = (Tt) X Short (tt) t t Tt tt Tt tt T t

The End Words to remember Words to remember  Dominant  Recessive  Homozygous  Purebred  Heterozygous  hybrid  Punnett Square  Incomplete Dominance