Chapter 6 - Pedigrees Flashcards
You are studying YFD (your fav disease). While looking at a pedigree you notice that one of five children have the symptoms of YFD, yet neither parent has the disease. What can you conclude? A. The trait is X-linked B. The trait is autosomal dominant C. The trait is autosomal recessive D. Not enough info
C. The trait is auto recessive.
What characteristic would you NOT expect to see in a pedigree of an X-linked recessive trait?
A. The trait is more commonly seen in males.
B. The trait can skip a generation.
C. The trait is commonly passed from father‘s to sons.
D. Whenever a daughter receives the trait, the father is affected.
E. An affected son’s mother either has the trait or is heterozygous (carrier).
C. The trait is commonly passed from father‘s to sons.
In studying an X-linked dominant trait, you examine a family with seven children. None of the three sons has the trait and all four daughters have the trait. What is the likely conclusion about the parents?
A. The mother has the X-linked dominant trait.
B. Both mother and father have the X-linked dominant trait.
C. This mutation likely arose during meiosis of either parent.
D. The father has the X-linked dominant trait.
E. We do not have enough dataTo make any to make any conclusions.
D. The father has the X – linked dominant trait.
Autosomal ____ traits appear in both sexes with ___ frequency, tend to ___ generations, are revealed in offspring whose parents were unaffected, are demonstrated in 1/4 of progeny when both ___ are ____, and appear more frequently in progeny of _____ matings.
recessive; equal; skip; parents; heterozygous; consanguine.
Autosomal____ traits appear in ____ sexes with ___ frequency; both sexes ____ the trait to their progeny; the trait usually does/doesn’t skip generations; affected offspring must have an affected parent; if one only one parent has they trait, they’re likely _____, and therefore will impact approx. __% of progeny; and unaffected parents do / do not transmit the trait.
dominant; both; equal transmit doesn't heterozygous; 50% do not
X-linked ____ traits affect more ___ than ___; the trait shows ____ inheritance meaning sons are born to ____ mothers (skips generations) who then pass the allele to their daughters; carrier mothers pass the trait to about __% of male progeny; all daughters of affected ___ are carriers; and ___ never pass along to their sons.
recessive; males; females crisscross; heterozygous/carrier 50% fathers fathers
X-linked ___ traits affect both males and females, but usually more ___ than ___ are affected. These traits do / do not skip generations. Affected ____ must have an affected mother; affected ___ have either an affected mother or father. Affected fathers pass the trait to all ____. Persons with the trait are almost always ____, and if it is a woman, she will pass the trait to ___% of her offspring, regardless of sex.
dominant; females; males. do not sons; daughters daughters heterozygous; 50%
This trait only affects males, is passed from fathers to all sons, and doesn’t skip generations.
Y-linked traits.
Huntington’s disease was identified using detailed ___ analyses.
pedigree
Autosomal dominant traits are usually ____; so nearly everyone with the disease is _____.
rare; heterozygous
Autosomal recessive traits might ___ several generations due to the small number of ____; they’re also more likely to appear more frequently in the progeny of ___ parents.
skip; progeny.
related
X-linked recessive vs. autosomal recessive? Include their frequency in sexes, and any patterns observed.
Autosomal recessive affect both sexes equally; X-linked recessive will occur in males more than females. Autosomal recessive traits can skip several generations and not show a very distinctive pattern whereas X-linked show a criss-cross pattern goin from father, to daughter (carrier) to (grand)son. X-linked recessive will never be passed from father to son.
Men with X-linked dominant traits always inherit from their _____, pass it to their _____ 100% of the time, but never pass it to their ____.
Mother; daughters, sons.
X-linked dominant vs. autosomal dominant - what’s one of the best ways to discern between the two?
In X-linked dominant, fathers pass 100% to their daughters and 0% to sons. In autosomal dominant, either parent passes to 50% of their offspring (assuming one of them is heterozygous).
Name one example of a Y-linked trait that was used to determine paternity over a century later.
Thomas Jefferson raped Sally Hemings.
