Topic: Genetics Aim: Why do offspring look similar to their parents? Do Now: 1.) List the similarities you notice amongst the family members 2.) State why they may have the same features

What is Genetics? The study of how variations of traits are inherited (or passed down) through living organisms Key Words geneAlleles Parent & offspring DNA Chromosomes Heredity

How are organisms genetically structured? Living organisms contain ___________________ inside of their nucleus which are made up of strands of ___________. This carries the hereditary information for the organism. Sections of the ____ code for a particular ________ that makes a specific trait. chromosomes DNA gene

Who was the Father of Genetics? Gregor Mendel He was a monk and gardener who studied Math and Science He was the 1 st to study heredity in pea plants He was 1 st to trace one trait passed down through several generations

How did Mendel study pea plants? He pollinated two parent pea plants and observed and recorded the traits of the new plant He referred to the traits as: Dominant- Seen often (Common) or Recessive- Not seen often (Uncommon)

Why Pea plants to study traits? Pea plants have fewer traits Can grow in a large amount (quantity) He could control the plants he desired to mate in his experiment

Topic: Genetics Aim: How can we examine the inherited traits found in offspring?

How do scientist today trace traits? One or more genes found at the same point on the chromosomes represents a trait Each person has a pair of genes for each trait One Allele from MOM One Allele from DAD

Alleles Each trait is represented by two versions called alleles One person may have two of the same version or one of each version The dominant allele is represented by a CAPITAL letter and the recessive is represented by a lower case letter

EXAMPLE: ALLELES TRAIT Dimples Dimples no dimples Dominant Recessive

Principles of Genetics Traits are passed on from one generation to the next. Traits are controlled by genes. Organisms inherit genes in pairs (2 alleles for every trait, 1 on each strand). Some genes are dominant, some are recessive. Dominant genes hide recessive genes when both are inherited by an organism. Some genes are neither dominant nor recessive (incomplete dominance)

What do scientists study in understanding a trait? Phenotype Is the physical appearance (___________) expressed (__________)by the organism because of their genotype feature shown

Genotype It is the combination of alleles (genes) in the chromosomes that determine a specific characteristic (trait) There are many types of Alleles for a trait Alleles can be _____________ or_____________ Dominant Recessive 1 mom & 1 dad

When the dominant allele is present the recessive trait is not seen in the phenotype Brown Eyes Brown Eyes Blue Eyes

How many ways can alleles be represented? Heterozygous Two different alleles present in the organism

Homozygous Two of the same alleles present in the organism Homozygous Dominant Homozygous Recessive

How do the genotype help determine the phenotype in human organisms? It is based upon the variations of alleles found on the __________________that each parent gives the offspring during the process of _______________________. chromosomes Fertilization

TOPIC: Genetics AIM: What are Punnett Squares? DO NOW: Explain the difference between genotype and phenotype

Punnett Squares Special chart Shows probability of possible gene combinations of offspring between 2 organisms

What is probability? The possibility that an event may or may not happen

¼ = 25% 2/4 = 50% 3/4 = 75% 4/4 = 100%

Steps to using a Punnett Square Step # 1 – Draw Punnett square Step # 2 – Apply maternal and paternal genotypes Step # 3 – Move alleles into appropriate boxes

Steps to reading a Punnett Square Step #1- Classify Genotypes Step # 2- Tally genotypes and phenotypes Step # 3-Calulate ratios and percentages Homozygous Dominant Heterozygous Heterozygous Homozygous Recessive GenotypesPhenotype 1 BB 2 Bb 1 bb Trait – Hair color Allele – Purple (Dom), Yellow (Rec) 3 Purple 1 Yellow

Heterozygous X Heterozygous

Heterozygous X Homozygous recessive

Heterozygous X Homozygous recessive

Homozygous Dominant X Homozygous Recessive

Is the range of differences between a male and female Biologically, male and females differ in ___________which are determined by____________________ sex traits genes Whether you are a male or female depends on the presence or absence of certain chromosomes.

FEMALE MALE The sex chromosomes are the X chromosome and the Y chromosome. Chromosomes determine gender. Human cells contain 23 pairs of chromosomes for a total of 46.

MOM DAD

A technique that involves a photograph of the chromosomes from a nucleus that are paired and arranged in size order.

The first 22 pairs are called autosomes and the last pair are sex chromosomes. When the chromosomes are different they are an X and a Y therefore it is a male