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4: Mendelian Genetics

Students predict offspring ratios using Punnett squares, apply Mendel's principles of segregation and independent assortment, and trace traits through pedigrees.

LibreTexts reference: Chapter 4: Mendelian Genetics LibreTexts

Matching Genetic Terms to Definitions

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Match each of the following genetic terms with their corresponding definitions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. homologous chromosomes
Drop Your Choice Here 2. gene
Drop Your Choice Here 3. genetics
Drop Your Choice Here 4. genomics
Drop Your Choice Here 5. locus

Drag one of the choices below:

  • A. scientific study of how genes control the characteristics of plants and animals
  • B. the structure, function, evolution, and mapping of genomes
  • C. the main elements of heredity
  • D. one chromosome from the mother and one chromosome from the father
  • E. the physical position of a gene within a chromosome
 

Matching Mendelian Cross Generations to Descriptions

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Match each of the following Mendelian crosses and generational stages with their corresponding descriptions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. backcross
Drop Your Choice Here 2. F2 generation
Drop Your Choice Here 3. P generation
Drop Your Choice Here 4. reciprocal cross

Drag one of the choices below:

  • A. two separate crosses where the traits of the male and female in one cross are switched in another cross
  • B. a generation with two homozygous individuals with different phenotype in a hybrid cross
  • C. a mating event where F1 generation individuals are bred with one of the original parental types
  • D. the second generation of offspring, descended from the F1 generation generation
 

Matching Mendel's Principles to Descriptions

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Match each of the following Mendel's Foundational Principles of Genetics with their corresponding descriptions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. Law of Segregation
Drop Your Choice Here 2. Principle of Dominance
Drop Your Choice Here 3. Principle of Paired Factors
Drop Your Choice Here 4. Law of Independent Assortment

Drag one of the choices below:

  • A. Dominant alleles are the ones that determine the phenotype of the hybrid organism.
  • B. Alleles for different traits are passed down without influencing each other.
  • C. Each parent passes a single allele for each trait to the offspring during sexual reproduction.
  • D. The genetic makeup for each character involves two alleles.
 

Matching Mendelian Genetics Terms to Definitions

Click to show Matching Mendelian Genetics Terms to Definitions example problem

Match each of the following Mendelian genetics terms with their corresponding definitions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. phenotype
Drop Your Choice Here 2. homozygous
Drop Your Choice Here 3. trait
Drop Your Choice Here 4. dominant

Drag one of the choices below:

  • A. all traits that can all be observed in an organism
  • B. an allele that masks another allele in the presence of both alleles
  • C. identical inherited versions of a gene from each biological parent
  • D. examples of a character's form include round or wrinkled seeds in plants
 

Matching Monohybrid Cross Genotypes to Phenotypes

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Match each of the following parental genotypes in monohybrid crosses with their corresponding descriptions of the progeny.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. aa × aa
Drop Your Choice Here 2. Aa × Aa
Drop Your Choice Here 3. AA × AA
Drop Your Choice Here 4. AA × Aa
Drop Your Choice Here 5. AA × aa
Drop Your Choice Here 6. Aa × aa

Drag one of the choices below:

  • A. Produces a 1:1 phenotype ratio in progeny
  • B. Yields offspring with 50% homozygous dominant and 50% heterozygous genotypes
  • C. Results in all homozygous dominant offspring
  • D. Produces only the recessive phenotype in progeny
  • E. Produces a 1:2:1 genotype ratio in progeny
  • F. Results in all heterozygous offspring
 

Genetic Terms from Definitions

Click to show Genetic Terms from Definitions example problem

Which one of the following genetic terms correspond to the definition 'scientific study of how genes control the characteristics of plants and animals'.

 

Mendelian Cross Types from Generational Descriptions

Click to show Mendelian Cross Types from Generational Descriptions example problem

Which one of the following Mendelian crosses and generational stages correspond to the description 'a genetic cross to combine traits from two different true-breeding parents'.

 

Mendel's Principles from Descriptions

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Which one of the following Mendel's Foundational Principles of Genetics correspond to the description 'Each organism has two alleles that influence a given characteristic.'.

 

Mendelian Genetics Terms from Definitions

Click to show Mendelian Genetics Terms from Definitions example problem

Which one of the following Mendelian genetics terms correspond to the definition 'one observable feature category of a group of organisms, such as flower color'.

 

Parental Genotypes in Monohybrid Crosses from Offspring Outcomes

Click to show Parental Genotypes in Monohybrid Crosses from Offspring Outcomes example problem

Which one of the following parental genotypes in monohybrid crosses correspond to the description of the progeny 'Produces a 1:2:1 genotype ratio in progeny'.

 

Offspring Survival Ratios in Lethal Allele Crosses

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In cats, allele T causes tailless in heterozygotes (Tt) but is lethal in homozygotes (TT). The parental cross is Tt x Tt.
If 80 conceptions occur, how many are expected to have the normal phenotype?

 

Dominance Types in Monohybrid Crosses

Click to show Dominance Types in Monohybrid Crosses example problem
Gene 1 Female ♀
R r

Male
♂

 R RR Rr
r Rr rr

Two organisms were crossed in a monohybrid experiment. The offspring showed three blue (■) and one yellow (■) phenotype.
What type of dominance best explains these results?

 

Monohybrid Cross Outcomes

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Which parental genotype combination would generate only homozygotes offspring?
 

Parent Genotypes from Offspring Ratios

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A pea plant with round seeds known to be heterozygous is crossed with an individual of unknown genotype. In a large litter of 8 offspring, 6 show round seeds and 2 show wrinkled seeds.
Assume a single gene with A dominant to a. What is the most likely genotype of the unknown parent?

 

Offspring Sex Distribution Using the Binomial Model

Click to show Offspring Sex Distribution Using the Binomial Model example problem

Model: Binomial →

⟮  n  ⟯
k
⋅pk⋅qn-k
In this scenario, assume that each child is born independently with the same chance of being either sex. The event outcomes are mutually exclusive, so we can apply the binomial model to determine the probability of a specific combination.
A woman has ten (10) children. What is the probability that she has exactly six (6) boys ♂ and four (4) girls ♀?
 

Punnett Square Results for Flower Color Inheritance

Click to show Punnett Square Results for Flower Color Inheritance example problem
In his experiments, Mendel discovered that the purple flower phenotype was dominant to the white flower phenotype. Which one of the following Punnett squares represents a cross of two different white flower plants of unknown genotype?
 

Inheritance Patterns from Pedigrees (Single Diagram)

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Examine the pedigree above. Which one of the following patterns of inheritance is most likely demonstrated in the above pedigree inheritance?
 

Pedigree Diagrams from Inheritance Patterns (Standard Layout)

Click to show Pedigree Diagrams from Inheritance Patterns (Standard Layout) example problem

Match the following pedigrees to their most likely inheritance type.
Note: each inheritance type will only be used ONCE.

Your Choice Prompt
Drop Your Choice Here 1.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     
 

 
Drop Your Choice Here 2.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 
Drop Your Choice Here 3.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     
 

 
Drop Your Choice Here 4.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     
 

 
Drop Your Choice Here 5.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 

Drag one of the choices below:

  • A. y-linked
  • B. x-linked dominant
  • C. x-linked recessive
  • D. autosomal dominant
  • E. autosomal recessive
 

Pedigree Diagrams from Inheritance Patterns (Randomized Layout)

Click to show Pedigree Diagrams from Inheritance Patterns (Randomized Layout) example problem

Match the following pedigrees to their most likely inheritance type.
Note: each inheritance type will only be used ONCE.

Your Choice Prompt
Drop Your Choice Here 1.

         
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
 
   
   
         
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 
Drop Your Choice Here 2.

           
   
   
 
       
   
   
   
   
   
   
   
   
   
   
     
   
   
         
   
   
   
   
   
   
   
   
   
   
   
   
   
   
             

 
Drop Your Choice Here 3.

       
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
 
   
   
             
   
   
 
   
   
   
   
   
   
     
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                         

 
Drop Your Choice Here 4.

     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
         
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                 

 
Drop Your Choice Here 5.

           
   
   
 
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
               
   
   
 
   
   
   
   
   
   
   
   
   
   
         
   
   
   
   
   
   
                         

 

Drag one of the choices below:

  • A. autosomal recessive
  • B. autosomal dominant
  • C. x-linked dominant
  • D. x-linked recessive
  • E. y-linked