Chapter 9 Lesson 2: Different Ways Alleles Cooperate

NAME ______DATE ______PER_____

Chapter 9 Lesson 2: Different Ways Alleles Cooperate

Some patterns of inheritance do not follow Mendel’s laws, and are more complex. Below are some examples of these other types of inheritance.

A. ______: One allele is not completely dominant over another, therefore the heterozygous phenotype lies somewhere between the two homozygous phenotypes- A BLEND.

EX/ Japanese four o’clock plants RR = red; WW = white; RW = pink

B. ______: A gene that exists in several different forms (more than two)

C. ______: Phenotypes produced by both alleles are clearly expressed

EX/ RR = red; WW = white; RW = red and white spots

EX/ BLOOD-TYPES: ______

• For Human blood, there are _____ alleles for blood type, _____, ______, and ______

• For Human blood, ____ is codominant to the ____ allele both ____ and ____ alleles are dominant to the _____ allele

The result of the above is the possibility of 4 phenotypes:

Practice Problem #1: A type AB person is crossed with a type O person. What are the genotypic and phenotypic ratios of this cross?

Parent Genotypes: ______X ______

Square: Genotypic Ratio: Phenotypic Ratio:

Practice Problem #2: What two genotypes will produce all four phenotypes of blood?

Parent Genotypes: ______X ______

Square: Genotypic Ratio: Phenotypic Ratio:

D. ______: traits that are produced by the interaction of several genes.

Phenotype is result of the additive effects of two or more genes, produces a continuum of phenotypes.

EX/Skin color, height, IQ

Chapter 9 Lesson 3: The Importance of Sex Chromosomes

SEX-LINKED GENES: ______

In humans, the 23rd pair of chromosomes are called the ______.

Females are ______and males are ______for this pair.

If we cross a male and a female: Genotypic Ratio Phenotypic Ratio

Therefore, the ______determines the sex of the child.

EX/Hemophilia:A disorder when a person’s ______

□The X chromosome can carry either a:

• ______allele, written as ______, which codes for ______blood clotting
• ______allele, written as ______which codes for ______blood clotting (the hemophilia gene)

Female Genotypes Female Phenotypes Male Genotypes Male Phenotypes

EX/Color Blindness: A disorder where a person ______

Female Genotypes Female Phenotypes Male Genotypes Male Phenotypes

□Therefore, in order for ______to have hemophilia or color blindness, they only need ______recessive allele. (b/c they only have ______chromosome)

□Females need ______recessive alleles to show these traits (b/c they have ______chromosomes).

□Therefore, more ______tend to show sex-linked traits.

Practice Problem: Cross a woman that is a carrier (heterozygous) for hemophilia with a male hemophiliac.

Parental Genotypes: Mom : ______Dad: ______

Cross: Genotypic Ratio Phenotypic Ratio

Practice Problem: Cross a woman that is color blind with a man with normal vision.

Parental Genotypes: Mom : ______Dad: ______

Cross: Genotypic Ratio Phenotypic Ratio

2. PEDIGREES: Chart that shows the relationships within a family – shows the presence or absence of a trait according to the relationships between parents, siblings, and offspring.