Mendel & Genetics 2018-19

Genetics Genetics is the study of heredity. Heredity is the passing of a physical trait from parent to offspring. Traits are different forms of characteristics ex. eye color, hair color

Gregor Mendel Wondered why pea plants are different- tall, short, green seed, yellow seed, etc. He cross-pollinated pea plants (took pollen from 1 plant to another) in order to see how traits were passed on Considered the Father of Genetics

Mendel Continued Mendel figured out that traits are carried in pairs on structures called chromosomes. Chromosomes are made up of DNA and have specific sections called genes.

Mendel’s Experiments Purebred (homozygous)- an offspring with the same exact traits ex. a purebred short pea plant would have short parent plants Hybrid (heterozygous)- offspring has two different forms of a trait ex. a hybrid tall pea plant could have a short and tall parent

Generations P Generation- Parent generation F1- Offspring of the P generation F2- Offspring of the F1 generation

Genes & Alleles Gene- a factor that controls a trait. You get one from each parent. Alleles- Different forms of a gene Ex. one allele for short, one allele for tall ** Traits are controlled by the alleles inherited from parents**

Forms of Alleles Dominant: trait will ALWAYS show up when present represented by a capital letter ( AA = 2 dominant alleles) Recessive: trait is HIDDEN when there’s a dominant allele represented by a lowercase letter (Aa= 1 dominant, 1 recessive so recessive DOES NOT show up)

T= brown hair t= red hair PRACTICE! T= brown hair t= red hair Tt: TT: tt: G= short g= tall GG: gg: Gg:

Practice! Label as hybrids or purebreds: Tt: TT: tt: 4. GG: 5. gg:

Phenotype & Genotype Phenotype: An organism’s physical appearance like widow’s peak or attached earlobes. Genotype: An organism’s genetic make up like the allele combinate (tt or Tt or TT)

Phenotype/Genotype Practice T= brown hair t= red hair Tt: TT: tt: G= short g= tall Homozygous short: Heterozygous short: Purebred tall:

Punnett Squares This is a table that shows the probability of an individual getting a trait.

Punnett Square Step 1: Put the parent’s alleles on the side and top of the table.

Punnett Square Step 2: Drop the top letters down. Bring the side letters across.

Practice! B= Tongue roller T= Dimple b= Can’t roll tongue t= No dimple

Practice! 1st Punnett Square: 2nd Punnett Square: What percentage of What percentage of Offspring will not be offspring will have Able to roll their dimples? tongue?

Sources http://zupnija-stepanja-vas.rkc.si/oce-gregor-mendel-6-januar-1884-20-julij-1822 http://blog.earthbark.com/ http://emilym-emily.blogspot.com/ http://cikgurozaini.blogspot.com/2010/06/genetic-1.html http://library.thinkquest.org/C0118084/Gene/Genetic_variation/examples.htm http://abagond.wordpress.com/2011/06/23/mendel/