Science 30 – Unit 1Living Systems Respond to their Environment

Lesson 6 – Inheritance

This is covered in section 2.2 of your textbook from pages 93-103

What types of things do you inherit from your parents when it comes to genetics?

•  Certain traits are passed on from parent to offspring called______traits

–  Located on ______

–  ______

•  Others, acquired traits, may be possessed by the parent but are not passed on

–  Environmentally caused

–  ______

Alleles

•  Located on chromosomes

•  Two versions of each (one from Mom and one from Dad)

•  Can be the same or different

Dominant vs. Recessive

•  DOMINANT traits (bully) come from DOMINANT alleles

–  Represented by uppercase letters

–  Will ______

•  RECESSIVE traits come from RECESSIVE alleles

–  Represented by lowercase letters

–  ______by the dominant allele

Punnet Squares

•  If alleles are known we can predict probability of dominant vs. recessive

•  Two pea plants in the parent generation are Pp. Use a punnett square to predict the % probability that a plant in the 1st generation offspring will be white.

•  ______

•  ______

Practice

•  Two parents each possess the dominant allele R for tongue rolling and the recessive allele r for non-tongue rolling. Draw a punnett square to determine the % probability that their offspring ARE able to roll their tongues.

•  One parent possess the dominant allele R and the recessive allele r while the other parent possesses two recessive copies. Draw a punnett square to determine the % probability that their children are able to roll their tongues.

Terminology

•  ______- having two copies of the same allele for a given trait (PP or pp)

•  ______– having a dominant allele and a recessive allele for a given trait (Pp)

•  ______– description of the alleles

•  ______– physical traits of the organism

Inheritance

•  Not always as simple as two alleles, some traits are controlled by ______

–  Ex: Blood Type

–  Three forms ______

Table of Blood Types
Genotype / Phenotype
OO / Type O blood
AA or AO / Type A blood
BB or BO / Type B blood
AB / Type AB blood

Determine Gender

•  Mom ALWAYS has ______because she is female

•  Dad has ______because he is male so he can contribute sperm carrying X or sperm carrying Y

•  Use a punnett square top determine inheritance of X and Y chromosomes

Sex-Linked Inheritance

•  X and Y do more than just determine gender

–  Colour blindness

•  Punnett square is slightly different

•  EX: heterozygous woman with full vision (XN Xn) has children with a colour blind man (XnY)

Homework

•  Practice Problems p.97-101 #16-26

•  Lab p.102 Analysis #1-6 (Hand-in Assignment)

•  Questions p.104 #1-7

Lab Data

Dominant Phenotype
(A) / Recessive Phenotype
(B)
1 / Hair Type (Curly / Straight)
2 / Hairline (Widow’s peak / Straight)
3 / Ear Lobes (Free / Attached)
4 / Handed (Right / Left)
5 / Thumb (Left over right / Right over Left)
6 / Finger (Ring finger longer / Index Finger Longer)
7 / Thumb Curve (Hitchhiker / Straight)
8 / Second Toe (Toe Longer / Big Toe Longer)