11.1 – Intro. To genetics FQ: What key genetics vocabulary do I need to understand before I can start learning about genetics? ET: Read the chapter mystery on pg. 307. Write down the question that is to be investigated as we go through the chapter.

Basic vocabulary to help in our study of genetics Allele Fertilization Principle of dominance Trait Segregation Hybrid gamete Gene

Vocabulary Gametes: These are sex cells Ex. Animals have sperm and egg Ex. Plants have pollen and ovum Fertilization: in sexual reproduction, this is the joining of gametes Ex. Sperm and egg form a cell that develops into an embryo

Vocabulary Trait: the physical expression of a gene, basically a characteristic Gene: the actual information in the DNA that determines traits. This is what is passes from generation to generation Allele: Different forms of a trait The trait is height The different alleles for height could be short or tall Genetics: the study of heredity – the passing of genetic information from one generation to the next

Traits VS. Alleles The trait - eye color The trait - thumb shape Alleles (forms): blue, brown, green The trait - thumb shape Alleles: bent or straight The trait - hair line Alleles: widows peak or straight

Vocabulary continued… Segregation: When homologous pairs of chromosomes (one moms and one dads) separate to make gametes (haploid cells) Principle of Dominance: some alleles are dominant over others

Lets look at some of these traits! Read through the “Quick lab” on pg. 311 Make the data table in your notebook Make your prediction according to step 2 Figure out your features Survey your friends!

11.1 - Gregor Mendel Learning Targets: Entry Task: Describe how Mendel studied inheritance in peas Summarize Mendel’s conclusions about inheritance Entry Task: Trait: fur pattern Alleles: ???? Pick a trait and list the possible alleles for that trait

Gregor Mendel 1822 Who: An Austrian monk What: developed an explanation for the mechanism of evolution

What Mendel did… F2 Generation P Parental F1 Generation

Genotype VS. Phenotype Phenotype: what form of the trait is expressed – what they look like! Tall Short Blue eyes etc… What every form of trait you see in that individual Genotype Homozygous – an organisms has two identical alleles, like “TT.” Both parents gave a tall allele Homozygous dominant Homozygous recessive Heterozygous – an organisms has two different alleles, like “Tt.” Parents gave different forms of the height gene

Lets practice! For each set of alleles, write the genotype and phenotype. Straight hair is dominant over curly SS Ss ss Freckles recessive to no-freckles FF Ff ff Brown fur is dominant over white BB Bb bb

11.2 – Genotypes and Phenotypes ET: Choose letters and write the alleles for the given genotype Brown eyes is dominant over blue eye Homozygous dominant Heterozygous Homozygous recessive Widows peak is dominant over straight hair line Attached ear lobes is recessive to unattached

Mendel’s Conclusions Inheritance is determined by factors that are passed from one generation to the next, genes. Some forms of a trait (alleles) are more dominant than others, the principle of dominance

Biology – Punnett Squares LT: Today I will… Make predictions about patterns of inheritance Use mathematical methods for solving genetics problems (Punnett square) ET: Write the genotype for an individual who has attached ear lobes, has a widows peak, and hairy fingers eeWWFF eeWwFw

Punnett Squares We will cross two homozygous parents TT – homozygous dominant tt – homozygous recessive T T t t

11.2/11.3 – Probability and Patterns of Inheritance LT: Today I will… Explain the principle of independent assortment Use Mendel’s principles to solve punnett square problems ET: What are the possible allele combination in the following individuals gametes Genotype is TTRR Genotype is ttrr Genotype is TtRr

Lets practice making gametes! If the genotype is… Bbyy bbYY BBYy HHJJII Hhjjii HhJjIi Possible gametes are… By by bY BY By HJI Hji hji HJI HjI Hji HJi hJI hji hJi hjI

The Two-Factor Cross: 2 traits P generation: RRYY homozygous dominant for round yellow peas x rryy homozygous recessive for wrinkled green peas RRYY Parent’s Gametes – rryy Parent’s Gametes - RY RY RY RY ry ry ry ry

Lets cross 2 F1 generation plants! All the possible combos. RY Ry rY ry RRYY RRYy RrYY RrYy RRyy Rryy rrYY rrYy rryy

Other forms of Inheritance Incomplete Dominance = A blending of both alleles Ex. The allele for red petals is not completely dominant over the allele for white petals so the offspring has pink petals

Continued… Co-dominance = Both traits will show up. They are not blended together, you actually see both Ex. The allele for black feathers is co-dominant with the allele for white feathers so the bird is black and white spotted

Continued… Sex linked traits – some inherited traits are located on the chromosomes that determine gender, the X or Y. Females have two X chromosomes: XX genotype Males have one of each: XY genotype EX. Hemophilia is an X-linked recessive disorder. This means… If you’re a make, XY, and you inherit a recessive allele it will show up because you do not have another X chromosome with a normal dominant allele to over power it.

Meiosis Simulation http://www.biomanbio.com/GamesandLabs/Genegames/snurfle_meiosis_and_genetics.html

Get your Snurfle worksheet out for reference Meiosis Get your Snurfle worksheet out for reference ET: What is meiosis? Learning objectives: Explain the process of meiosis Compare mitosis and meiosis Identify crossing over Explain how linked genes work

Independent Assortment Genes on different chromosomes segregate independently during the formation of gametes (meiosis)

Crossing Over

Polygenic Traits Traits controlled by two or more genes: eye and skin color. So there are several different combinations possible *Incomplete dominance – In a heterozygote there is a blending of the two traits ex. Red and white produce pink *Co-dominance – In a heterozygote both traits are visible ex. Black and white speckled chickens

Focus Question: Epigenetics – does the environment have a role in how genes determine traits? Make a claim about this