BIOL 3001 MIDTERM QUESTIONS &
ANSWERS(GRADED A+)
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
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
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: 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
Recessive Backcross (Aaxaa) - ANSWER1 AA : 1 aa; 1 Aa : 1 aa
Dominant Backcross (AaxAA) - ANSWER1 AA : 1 Aa; All A—
Chi Square Test - ANSWERused to compare what we observe (observed data)
against what was expected (expected data). The goal is to estimate how much the
results that we obtain deviate from what we predicted based on a specific
hypothesis.
Chi Square formula - ANSWERχ2 = Σ (o-e)2/e
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.
ANSWERS(GRADED A+)
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
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
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: 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
Recessive Backcross (Aaxaa) - ANSWER1 AA : 1 aa; 1 Aa : 1 aa
Dominant Backcross (AaxAA) - ANSWER1 AA : 1 Aa; All A—
Chi Square Test - ANSWERused to compare what we observe (observed data)
against what was expected (expected data). The goal is to estimate how much the
results that we obtain deviate from what we predicted based on a specific
hypothesis.
Chi Square formula - ANSWERχ2 = Σ (o-e)2/e
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.
