What exactly are Chromosomes, DNA and Genes? Introduction to Genetics

Introduction to Genetics Video

Chromosome 46 inside every cell Chromosomes are in the cell in pairs. One came from mom and one came from dad. Mom’s ChromosomeDad’s Chromosome

DNA DNA - deoxyribonucleic (say: dee-ox- see-ri-bo-nyoo-clay-ik) acid Long strands of genetic code Makes up chromosomes in plants and animals DNA

Genes Tiny pieces of DNA that are instructions for specific traits

Traits Things that you inherit from your parents Examples:Examples: Hair color, eye color and having freckles or not Through sexual reproduction you inherited a set of traits

Traits Pairs of letters are used to define genes in your body CAPTIAL LETTERS DOMINANTCAPTIAL LETTERS are used to represent DOMINANT genes lower case letters recessivelower case letters are used to represent recessive genes Dominant trait: If you receive even one of these in the pair, you will get a specific trait. Recessive trait: You have to have two of these in the pair to get a specific trait

Genotypes The letter associated with the gene ▫Example: W (dominant widow’s peak) w (recessive no widow’s peak)

Phenotypes This is the "outward, physical manifestation“ The actual physical trait ▫Example: Widows Peak

Allele Allele: aAAllele: The single letter such as the a or the A.

Heterozygous Heterozygous – having two different alleles Aa Bb

Homozygous Homozygous – having the same alleles AA BB

Practice: B – brown hair b – red hair My genes: Bb What color hair will I have? Is Bb the phenotype or the genotype? Are my genes heterozygous or homozygous?

Practice: A – attached earlobea – unattached earlobe My genes: aa What will my earlobes do? Is attached earlobe the phenotype or the genotype? Is my genotype homozygous or heterozygous?

Practice: D – dimplesd – no dimples My genes: DD Do I have dimples or not? What is the genotype? Is my genotype heterozygous or homozygous?

Quiz F – frecklesf – no freckles My genes: FF Do I have freckles or not? What is the phenotype? What is the genotype? Is my genotype heterozygous or homozygous? Which parent carried the dominant gene?

What is a PUNNETT SQUARE? probability A tool to predict the probability of certain traits in offspring that shows the different ways alleles can combine A way to show phenotype & genotype A chart that shows all the possible combinations of alleles that can result when genes are crossed

Punnett Squares Video

Using a PUNNETT SQUARE To set up a Punnett square, draw a large square, and then divide it into 4 equal sections (also squares). It should look something like this:

Using a PUNNETT SQUARE Now you need two parents to mate, ones with a known genotype For example, Brown hair (genotype BB) and blonde hair (genotype Bb). BB x Bb blonde In this scenario, the Mom has brown hair. The dad blonde hair.

Using a PUNNETT SQUARE The two-letter combinations are the possible genotypes of offspring They are: BB, Bb, BB, and Bb genotypes From this it is possible to determine the probability (chance) that a baby will have a brown phenotype (2/4 or 50%) or a blonde phenotype (2/4 or 50%)

Using a PUNNETT SQUARE Place one of the parents on top, and one on the left. You should get a something similar to this: Bb B B What is the probability of having the recessive trait? 100 %

Punnet Square Practice with White Boards h h H H What is the probability of having the dominant trait? 100 %

Punnet Square Practice with White Boards w W w W What is the probability of having the recessive trait? 25%

Punnet Square Practice with White Boards w W w w What is the probability of having the dominant trait? 50%

Does it work with animals and plants? Yes, all of this works the same way in determining the outcome of combining animals and plants. How can we relate this to selective breeding? How can we relate this to genetic engineering?

Pedigree Charts _embedded&v=Wuk0W10EveUhttp:// _embedded&v=Wuk0W10EveU

Extracting DNA from a Banana Lab Expectations: 1.C.H.A.M.P.S. Group Work ▫Conversation: Voice Level 1-2 ▫Help: 3 Fingers Signal ▫Activity: Complete Lab and Activity Sheet ▫Movement: Stay in Seats, Use Finger Signals ▫Participation: Discuss, Help with Lab, Group Jobs

DNA Extraction Virtual Lab raction/# raction/#

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