Genetics N’ Stuff

Who Came Up with This? Gregor Mendel Proposed theory of heredity Traits are passed from parents to offspring

He worked with pea plants tall short

Why did the tall override the short? Dominant= trait that is bossy Recessive= trait that gets masked

Section 10.1 Summary – pages 253-262 Tall plant Short plant tall plant passes on “T” allele = letter dominant over “t” allele T T t t T t All tall plants T t Section 10.1 Summary – pages 253-262

Why does each trait have 2 letters? A letter is passed from each parent Hello! Heredity

Homozygous- 2 same size letters HH or hh Heterozygous= different size letters Hh

Physical trait= round snoot!! If I have genotype Ww, and W=round snoot and w=pointy snoot, what will my phenotype be? Physical trait= round snoot!!

Phenotype= physical trait Genotype = letters or alleles

Let’s do an example with a punnett square!

If there are only brown dominant chickens and white recessive chickens, how could you get a red chicken? Incomplete dominance

Incomplete= 2 phenotypes mix to make a medium trait Codominance= when both phenotypes show up Example= blood type

But what about height? There are way more than 2 or 3 sizes of person! Polygenic Traits

Polygenic Traits More than one allele controls it Examples: height,

Traits can also be linked by 9sex Only boys get color blindness Hemophilia