BIOL 3001 Midterm EXAM QUESTIONS
WITH COMPLETE ANSWERS!!
Pedigree - Answerchart that shows the presence or absence of a trait according to the
relationships within a family across several generations
Complete Penetrance - AnswerThe gene or genes for a trait are expressed in all the
population who have the genes
Incomplete Penetrance - Answerthe genetic trait is expressed in only part of the
population
3 assumptions when determining the mode of inheritance - Answer1. The trait
displays Complete Penetrance.
2. The trait is considered Rare-in-Population.
3. The traits you examine are not Y-Linked.
Pedigree symbols: A transparent circle - AnswerUnaffected female
Pedigree symbols: A transparent square - Answerunaffected male
Pedigree symbols: filled circle - Answeraffected female
Pedigree symbols: filled square - Answeraffected male
Pedigree symbols: diamond - Answergender not specified
Pedigree symbols: line through square, circle, or diamond - Answerdeceased
individual
Pedigree symbols: have filled square or circle - Answercarrier individual (usually
heterozygous)
Pedigree symbols: two shapes branching from the same node - Answerdizygotic twins
Pedigree symbols: two shapes branching from the same node with extra line connecting
them - Answermonozygotic twins
Pedigree symbols: black arrow pointing to square, circle, or diamond on tree -
Answerproband: individual who prompted pedigree
, Pedigree symbols: Brackets around an individual - Answeradopted individual
Patterns that indicate autosomal recessive trait - Answer- both parents of the affected
individual must be unaffected
-the trait skips a generation or it may disappear and reappear across generations
Patterns that indicate autosomal dominant trait - Answer-Trait appears in every
generation
-an affected individual must have at least one affected parent
-affected individuals will usually have an affected offspring
Patterns that indicate x-linked dominant trait - Answer-More females than males are
affected, as females have two chances to receive the trait (XX)
-An affected individual must have at least one affected parent
-The trait cannot skip a generation
Patterns that indicate sex-linked recessive trait - Answer-more males than females
are affected because only one copy is needed (XY)
-most affected males usually receive the allele from their mother
-affected females must have an affected father
Patterns that indicate holandric (Y-linked) trait - Answer-trait limited to males only in
humans (mammals)
-an affected male must have an affected father
-very rare mode of inheritance since carried on Y chromosome
mode of inheritance - AnswerManner in which a genetic trait or disorder is passed
from one generation to the next
Drosophila melanogaster - Answerthe Family Drosophilidae, Order Diptera (which
also includes flies, mosquitoes and midges) and the Class Insecta (insects).
common name for Drosophila melanogaster - Answerfruit fly
How many chromosomes do fruit flies have? - Answer2N=8 (4 pairs)
Sex-determination in fruit flies - Answerlygaeus mode
Lygaeus mode - AnswerPresence of different sex chromosomes
3 characteristics to distinguish gender in fruit flies - Answer1. Females are larger than
males.
2. Females have a "knob" (ovipositor) on the tip of the abdomen.
WITH COMPLETE ANSWERS!!
Pedigree - Answerchart that shows the presence or absence of a trait according to the
relationships within a family across several generations
Complete Penetrance - AnswerThe gene or genes for a trait are expressed in all the
population who have the genes
Incomplete Penetrance - Answerthe genetic trait is expressed in only part of the
population
3 assumptions when determining the mode of inheritance - Answer1. The trait
displays Complete Penetrance.
2. The trait is considered Rare-in-Population.
3. The traits you examine are not Y-Linked.
Pedigree symbols: A transparent circle - AnswerUnaffected female
Pedigree symbols: A transparent square - Answerunaffected male
Pedigree symbols: filled circle - Answeraffected female
Pedigree symbols: filled square - Answeraffected male
Pedigree symbols: diamond - Answergender not specified
Pedigree symbols: line through square, circle, or diamond - Answerdeceased
individual
Pedigree symbols: have filled square or circle - Answercarrier individual (usually
heterozygous)
Pedigree symbols: two shapes branching from the same node - Answerdizygotic twins
Pedigree symbols: two shapes branching from the same node with extra line connecting
them - Answermonozygotic twins
Pedigree symbols: black arrow pointing to square, circle, or diamond on tree -
Answerproband: individual who prompted pedigree
, Pedigree symbols: Brackets around an individual - Answeradopted individual
Patterns that indicate autosomal recessive trait - Answer- both parents of the affected
individual must be unaffected
-the trait skips a generation or it may disappear and reappear across generations
Patterns that indicate autosomal dominant trait - Answer-Trait appears in every
generation
-an affected individual must have at least one affected parent
-affected individuals will usually have an affected offspring
Patterns that indicate x-linked dominant trait - Answer-More females than males are
affected, as females have two chances to receive the trait (XX)
-An affected individual must have at least one affected parent
-The trait cannot skip a generation
Patterns that indicate sex-linked recessive trait - Answer-more males than females
are affected because only one copy is needed (XY)
-most affected males usually receive the allele from their mother
-affected females must have an affected father
Patterns that indicate holandric (Y-linked) trait - Answer-trait limited to males only in
humans (mammals)
-an affected male must have an affected father
-very rare mode of inheritance since carried on Y chromosome
mode of inheritance - AnswerManner in which a genetic trait or disorder is passed
from one generation to the next
Drosophila melanogaster - Answerthe Family Drosophilidae, Order Diptera (which
also includes flies, mosquitoes and midges) and the Class Insecta (insects).
common name for Drosophila melanogaster - Answerfruit fly
How many chromosomes do fruit flies have? - Answer2N=8 (4 pairs)
Sex-determination in fruit flies - Answerlygaeus mode
Lygaeus mode - AnswerPresence of different sex chromosomes
3 characteristics to distinguish gender in fruit flies - Answer1. Females are larger than
males.
2. Females have a "knob" (ovipositor) on the tip of the abdomen.
