BIOL 1140: Inheritance of Blood Types

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Questions and Answers

What is the primary reason Type O blood is considered the 'universal donor'?

It has no antigens, preventing cross-reaction. (correct)

It can react with any blood type.

It contains both anti-A and anti-B antibodies.

It has both A and B antigens.

How many possible blood type phenotypes are there given the ABO blood system?

4 (correct)

In a cross between two heterozygous individuals for Type A blood, what is the genotypic ratio of their offspring?

1:2:1 (correct)

1:1

3:1

2:2

What inheritance pattern is demonstrated by the expression of both A and B antigens in AB blood type?

Codominance Signup and view all the answers

If Patience (heterozygous Type A) and Justice (heterozygous Type B) have a child, what is the chance that the child will have Type O blood?

25% Signup and view all the answers

What is the possible genotype for a person with Type B blood?

IBIB Signup and view all the answers

What does the notation 'i' represent in the context of ABO blood genetics?

A recessive allele Signup and view all the answers

Which of the following best describes the blood antigens present in a type A individual?

A antigens only Signup and view all the answers

What is the commonality percentage of Rh+ blood type in the US?

84% Signup and view all the answers

Which sex chromosomes do males possess?

XY Signup and view all the answers

What determines biological sex at conception?

The sperm from the male Signup and view all the answers

Which chromosome has a larger number of genes, X or Y?

X chromosome Signup and view all the answers

In a dihybrid cross involving ABO and Rh antigens, what is the expected ratio for obtaining a child with a specific combination of blood types?

9:3:3:1 Signup and view all the answers

What kind of inheritance pattern is defined by genes located on the X chromosome?

X-linked Signup and view all the answers

What is the primary difference between biological sex and gender?

Biological sex is based on genetics, while gender is a social construct. Signup and view all the answers

What is a characteristic of X-linked recessive traits?

They are more often expressed in males due to the presence of one X chromosome. Signup and view all the answers

What genetic notation represents a female who is a carrier of an X-linked recessive trait?

XHXh Signup and view all the answers

Why are X-linked recessive traits more commonly expressed in males compared to females?

Males lack a backup X chromosome. Signup and view all the answers

Which of the following disorders is NOT classified as an X-linked recessive disorder?

Cystic Fibrosis Signup and view all the answers

If a father has an X-linked recessive trait and has a daughter with a mother who is homozygous for normal traits, what is the probability that their daughter will express the trait?

0% Signup and view all the answers

What is the likely consequence of an allele being hemizygous in males?

Direct expression of the trait regardless of allele type. Signup and view all the answers

What do the notations XHY and XhY indicate for a male's genotype?

Hemizygous for a dominant/recessive trait. Signup and view all the answers

In the context of X-linked inheritance, which statement accurately describes factors affecting the expression of traits in females?

Females only express traits if both alleles on their Xs are recessive. Signup and view all the answers

How does Duchenne Muscular Dystrophy primarily affect individuals who carry the gene?

It causes progressive muscle wasting. Signup and view all the answers

Study Notes

Introduction to Inheritance

Course name: BIOL 1140
Course topic: Inheritance of Blood Types & Sex-linked Traits
Instructor: Susan Cordova (Tappen)

Codominance

Both alleles are dominant, resulting in both phenotypes being expressed equally.
No recessive alleles; use superscripts instead of lowercase letters.
Example: Roan cattle
- CBCB = Brown
- CWCW = White
- CBCW = Roan

ABO Blood Types - General Information

RBCs vs plasma:
- RBCs (red blood cells) have antigens (A, B, both A&B, or none) on their surface.
- Plasma contains antibodies (anti-A, anti-B, both, or none).
Most blood donations are of only RBCs.

ABO Blood Types - General Info (Continued)

If donated RBC antigens react with the patient's plasma antibodies, agglutination (clumping) and hemolysis (rupture) can occur.
Type O blood is the universal donor.
Type AB blood is the universal recipient.

ABO Blood Types - Genetics

Multiple alleles:
- Three possible alleles: IA, IB, i
- Six possible genotypes: IAIA, IAi, IBIB, IBi, IAIB, ii.
- Four phenotypes: Type A, B, AB, or O blood.
Codominance: Both A and B antigens are expressed on heterozygotes.
Recessive/Dominant inheritance: IA and IB alleles are dominant; the i allele is recessive.

Blood Type & Multiple Allele Practice

Hermione and Ron are heterozygous for Type A blood.
Genotypic and phenotypic ratios are given in a Punnett square.

Blood Type & Multiple Allele Practice - Your Turn

Patience (Type A heterozygous) and Justice (Type B heterozygous) are parents.
Calculate the chance their child will have Type O blood.

What about Rh+ and Rh-?

Rh is another RBC antigen (Rh for Rhesus monkeys).
Rh+ allele is dominant over Rh-.
Approximately 84% of the US population is Rh+.
A dihybrid cross is possible with ABO and Rh antigens.

How is Biological Sex Determined?

Males are XY.
Females are XX.
Egg is X or X.
Sperm is X or Y.
Biological sex is determined by the sperm (male).

How is Biological Sex Determined? (Continued)

Punnett square with XX & XY
50% chance of male or female with every birth.
Biological sex is different from gender.
Gender is a social construct.

Sex-Linked Inheritance

Sex-linked traits are genes on either the X or Y chromosome.
X-linked traits are much more common and can be recessive or dominant.
The Y chromosome has approximately 78 genes. The X chromosome has approximately 2,000 genes.
Blood clotting proteins, muscle proteins, and vision proteins are examples of genes found on the X chromosome.

X-Linked Recessive Inheritance in Females

Notation: Use X and Y letters for the base letters.
Females can be heterozygous or homozygous.
Homozygous dominant (XHXH or XX).
Heterozygous (XHXh or XX*).
Homozygous recessive (XhXh or XX).
Females that are heterozygous are carriers.
Will only express the trait if both alleles are affected.

X-Linked Recessive Inheritance in Males

Males can only be hemizygous for X-linked traits (only one X chromosome).
Example: Xhy or Xhy (or X*y or Xy).
Males will express the trait regardless of whether it is dominant or recessive.

Examples of X-linked Recessive Disorders/Diseases

Duchenne Muscular Dystrophy (DMD):
- Mutation in the DMD gene that codes for dystrophin.
- Severe, progressive muscle wasting disease beginning in the lower limbs.
- Death is due to effect on muscles for breathing.
Red-Green colorblindness:
- Affects one of three types of cone receptors.
Hemophilia A:
- Mutation in the gene for "Factor VIII."
- Blood clotting protein.
- Spontaneous internal bleeding.

X-Linked Practice

Susan is homozygous for normal color vision. Juan is colorblind.
Calculate the genotypic/phenotypic ratios for their offspring.
Calculate the chances of their daughter/son being colorblind.

X-Linked Practice (Continued)

If the daughter (who is a carrier) has a son with someone who is not colorblind, what is the chance their son will be colorblind?
What if they have a daughter instead?

Pedigrees

Used to visually track inheritance through generations.
Useful for backing up inheritance from children to grandparents.
Symbols are used to represent individuals and their relationships.

X-Linked Practice with Pedigree

John has hemophilia. Neither parent has symptoms.
From whom did he inherit the disease?

X-Linked Practice with Pedigree (Continued)

Three children; son has DMD. Other two daughters do not.
Determine the genotypes and phenotypes of the parents.

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Description

This quiz covers the principles of inheritance related to blood types and sex-linked traits, focusing on codominance and the ABO blood group system. Understanding the interactions between RBC antigens and plasma antibodies is crucial for blood transfusions and genetics knowledge.