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Genetics. genes. Not jeans. And not Genes. The Study of 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?).
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Genetics genes Not jeans And not Genes The Study of genes
Vocab Cards You’re gonna need them for this unit!
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
Alleles: The different “forms” a gene may have For example: Eye color 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”. They are actually 2 “chromatids joined together like siamese twins Chromatid The shorter part of the “X” is the “p” arm The spot where the 2 chromatids join is called the centromere The longer part of the “X” is the “q” arm
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 (haploid) Diploid Zygote (fertilized egg)
How did we get here? Austrian Monk The “father of genetics” Gregor Mendel July 20, 1822 – January 6, 1884
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 2nd generation of offspring?
More… Dominant In a heterozygous gene, the trait that is expressed. Usually represented by a capital letter Recessive In a heterozygous gene, the trait that is not expressed. Usually represented by a lower-case letter Genotype The “makeup” of the allele Phenotype How the allele is expressed
For instance: What’s the genotype? RR The phenotype? Homozygous red Red Rr What’s the genotype? Heterozygous red The phenotype? Red What’s the genotype? rr The phenotype? White Homozygous white
Mendel’s “Laws” • Genes for traits comein 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.