Hand In Lab Notebook

The Genetics of Dog Breeds Dogs all belong to the same species, but there are 350-400 breeds Most breeds have only been around for a few hundred years What determines dog breeds is controlled by only 50 genes (by contrast human height alone is controlled by over 200 genes)

Human Influence On Dog Breeds Human selection of dogs for different tasks (hunting, herding, protection) influenced the expression of these ~50 genes

Figure 1: mRNA transcript fragments for the normal FGFR3 gene (N) and for the abnormal FGFR3 (A). NOTE: Mutations from the normal sequence are shown in bold underline. N1: …GCCCGACUGACC CUGGGCAAGCCC CUUGGGGAGGGC UGCUUCGGCCAG…   N2: …GCCCGGCUGACC CUGGGCAAGCCC CUUGGGGAGGGC UGCUUCGGCCAG… N3: …GCCCGGUUGACC CUGGGCAAGCCC CUUGGGGAGGGC UGCUUUGGCCAG… A1: …GCCCGGCUGACC CUGGGCAAGCCC CUUAGGGAGGGC UGCUUCGGCCAG… A2: …GCCCGGUUGACC CUGGGCAAGCCC CUUAGGGAGGGC UGCUUCGGCCAG… A3: …GCCCGGCUGACC CUGGGCAAGCCC CUUAGGGAGGGC UGCUUCGGCCAG…

Differences In Primary A.A. Sequence Amino Acid Sequence For Normal ALA|ARG|LEU|THR|LEU|GLY|LYS|PRO|LEU|GLY|GLU|GLY|CYS|PHE|GLY|GLU Amino Acid Sequence For Achondroplasia ALA|ARG|LEU|THR|LEU|GLY|LYS|PRO|LEU|ARG|GLU|GLY|CYS|PHE|GLY|GLU

Differences In Polarity Argenine (polar)

Small Nucleotide Ribonucleoprotein Part of the spliceosome Removes introns from mRNA transcript

What Are The Odds…?

Non-Fatal Injuries Zipper: 1: 2,600 Toilet: 1: 6,500 Alarm Clock: 1: 350,000 Bed: 1: 400

Fatal Injuries 1 Snake Bite: 1: 36,000,000 Dog Bite: 1: 20,000,000

Fatal Injuries 2 Ebola: 1: 14,000,000 Appendicitis: 1: 700

Fatal Injuries 3 Earth Destroyed By Meteor: 1: 20,000 You Alone Are Killed By Meteor: 1: 150,000,000,000

What Are The Odds That There Is An Exact Duplicate of YOU?

Unlikely… 3.2 billion nucleotides in human genome 97% of this is intron (non-coding), dropping the number of coding base pairs to 210,000 Two parents = 2^210,000 1 chance in 10^63,000 However, only ~108 billion humans have EVER been born.

Probability and Genetics Probability: The determination of certain outcomes based upon the number and type of possible outcomes Genetics: The determination of heritable outcomes due to the passage of DNA

If the central dogma dictates that DNA is copied in its entirety, and mitosis ensures that each daughter cell gets the same information as the previous, why do organisms need to be different?

Genetic Variety Genetic variety ensures that populations/species continue to survive despite changes in their ecosystems Populations that do not change genetically must have environments that rarely change

Sources of Genetic Variety Mutations Point Mutations (Single Nucleotide Polymorphisms) Frameshift/Nonsense Mutations Chromosomal Mutations Sexual Reproduction

Sexual v. Asexual Reproduction

Asexual Reproduction Def: Reproduction requiring only one parent/genetic source i.e. binary fission, parthenogenesis, budding PRO: Quick, Fast, Low Requirements CON: Low Genetic Variety

Sexual Reproduction Def: Reproduction requiring two parents/genetic sources i.e. conjugation, fertilization PRO: Genetic Variety CON: Need water, partners and GAMETES

GAMETES Def: Specialized reproductive cells (i.e. sperm, ovum) Gametes contain half the genetic content of other cells in the organism (yet still contain all of the genes) To produce another generation, gametes must be fused together to produce a ZYGOTE

Diploid v. Haploid Somatic (body) cells are DIPLOID (two sets of chromosomes) In each diploid cell, there are pairs of homologous chromosomes containing the same number and type of genes but NOT necessarily coding for identical proteins GAMETES are HAPLOID (only one set of chromosomes)

How does a cell go from diploid to haploid and yet retain all of the genes necessary for the organism?

Meiosis To develop gametes, a cell must undergo MEIOTIC DIVISION (i.e. MEIOSIS)