Genetics The Study of genes Not jeans And not Genes genes

Vocab Cards You’re gonna need them for this unit!

Define Genetics!

Genetics, Clarified How we get the Genes we get (Genes?) Gene: A section of DNA that encodes for a trait. (Trait?) Trait: Information communcated by the DNA. Sometimes obvious (eye color), sometimes hidden (enzymes). The gene is a sequence of the DNA, the trait is what the DNA encodes for, or “makes”.

Genetics, The Unit How these genes are passed from generation to generation. (inherited) How genes affect the way we look and Function. What’s the probability of a gene being inherited? How we can manipulate genes to get desired outcomes

For example: Eye color Alleles: The different “forms” a gene may have Important point: a gene actually encodes for a protein. “One gene: one protein”

Chromatin DNA double helix Histone proteins act as “spools DNA condenses into chromatin, which condenses into chromosomes chromatin

Chromosomes Chromosomes are generally represented as being shaped like an “X”. The spot where the 2 chromatids join is called the centromere The shorter part of the “X” is the “p” arm The longer part of the “X” is the “q” arm They are actually 2 “chromatids joined together like siamese twins Chromatid

How many? Most of the cells in our body have 46 (23 pair) chromosomes. Exception: Our Gametes (egg and sperm) have 23 single chromosomes

How many? Gametes Diploid Zygote (fertilized egg) (haploid)

How did we get here? Gregor Mendel July 20, 1822 – January 6, 1884 The “father of genetics” Austrian Monk

He gave peas a chance Experiments using pea plants with different alleles of same trait over multiple generations. The original “Mr Pea”

Some (more) basic terms: Parent generation (P) had 2 identical alleles. This is called pure or homozygous First set of offspring(f1) had 1 allele from each parent: 1 red, 1 white. This is called hybrid, or heterozygous

And still more vocabulary The f1 generation (hybrids) were then crossed with themselves. What was the genetic makeup of the 2 nd generation of offspring?

More… Dominant Recessive Genotype Phenotype In a heterozygous gene, the trait that is expressed. Usually represented by a capital letter In a heterozygous gene, the trait that is not expressed. Usually represented by a lower- case letter The “makeup” of the allele How the allele is expressed

For instance: Homozygous red Heterozygous red Homozygous white What’s the genotype? The phenotype? RR Red What’s the genotype? The phenotype? Rr Red rr White

Mendel ’ s “ Laws ” Genes for traits come in pairs (one from each parent). Law of dominance – one gene (allele) can prevent the appearance of another gene (allele). Law of segregation – when gametes form, pairs of genes separate so each gamete gets one of each gene pair. Law of independent assortment – During gamete formation, genes for different traits separate independently of one another.