Chapter 8Lesson 1

“Principles of Genetics”

I. Intro ActivityWhat similarities can you identify about the

fish shown in the following pictures?

II. Origin of Genetics

A. Mendel (1822-1884)1. History

a. Was a monk in Czechoslovakiab. Went to school as a science and math teacherc. Returned to being a monk

-tended the monastery garden-experimented with plants

2. Experiments

a. Used common pea plant

b. Characteristics remained the same

-Purple/white, long/short stem

c. Conducted many experiments over many generations

d. Fig 8-3 “Mendel’s seven traits”Seed Shape

Seed Color

Flower Color

Flower Position

Pod Color

Pod Shape

Plant Height

Dominant Round Yellow Purple Axial green Inflated Long

Recessive wrinkled green white Terminal Yellow constricted short

3. Results

x

F1

WW ww

Ww Ww Ww Ww

x

WwWw

F2

WW Ww Ww ww

a. Dominant – the trait that is expressed. (tall, blue eyes, etc.)

b. Recessive – the trait that is not expressed. It is carried from generation to generation.

c. Principle of Dominance – The dominant trait being carried out instead of the recessive trait.

4. Hypothesis

a. F1 – no recessive traits are shown

b. F2 – recessive traits appearc. Traits come from parents ( ½ sperm / ½ egg)

-called characters (genes)-dominant = capital-recessive = lower case

d. Punnett Square – chart used to predict combinations of genes among offspring.

-each square represents a possible zygote.

Parent #1

Parent #2Tt

Tt Tt

Tt

T = tall plantt = short plant

What is the % chance a tall plant is produced in F1? 100%

5. Terminology

a. – each alternative forms of a gene. (W (purple) / w (white))

b. – the combination of given traits (WW, Ww, ww)

c. – the appearance of a trait (what is dominant) Ww = purple

d. – a cell that has 2 of the same traits. (WW / ww)

e. – a cell that has 2 different traits. (Ww)

Allele

Genotype

Phenotype

Homozygous

Heterozygous

a. Use the FOIL methodb. Ex: (RrYy) x (RrYy)

-group similar traits

6. Two Trait

(Rr) (Yy)Parent #1

Firsts - RYOuters - Ry

Inners - rY

Lasts - ry

Parent #2

Same traits as parent #1

Possible

ZygotesRY Ry rY ry

RY

Ry

rY

ry

RRYY RrYY RrYyRRYy

RRYy

RrYY

RrYy

RRyy

RrYy

Rryy

RrYy

rrYY

rrYy rryy

rrYy

Rryy

Questions1. What is the percent chance of the

offspring being green?2. What is the percent chance of the

offspring being green and wrinkled?3. What is the percent chance of the

offspring being wrinkled?4. What is the percent chance of the

offspring being yellow and round?5. What is the percent chance of the

offspring being green and round?

25%

6.25%

25%

56.25%

18.75%

-Design a two trait Punnett Square.

-Fill it in-Incorporate 5 questions about the square and then answer them.-Make a replica Punnett Square (don’t fill it in) and write down the 5 questions you previously answered.**Lab #7 Due Wednesday**