In my family there are many soft paws. Left handedness can be traced
back to my Great Grandfather, (II) and my mother's side of the family. This
makes his genotype rr. His trait however was not passed on to my grandmother.
However I believe that my grandmother (112) became a carrier, or Rr, for this
gene. It is also possible that my grandfather (III) may have been a carrier but it is
not certain. In my pedigree I assumed that he would have been. I assumed this
becauseone of my cousins (IV2) along with myself (IV6) is left-handed. In order
for this to be possible two out of six of his children would have been carriers.
My Uncle Larry Ford (lIIl) is a carrier for this gene (Rr) as is his wife.
Out of their two sons one was left-handed, IV2, while the other, IV3 was not
Tyrone (IV2) is left-handed or rr. His son Seth,V2 is also left handed (rr) while
his son Gabriel, VI, is not. The fact that Tyrone was able to pass his left handed
gene on to his son rules out the possibility of this trait being either X-Linked
Recessive or X-Iinked Dominant My cousin Marion (IV3) who is Tyrone's
(IV2) brother has one affected daughter (V4), or rr, out of three children. All
three are girls. This means that both MarIon and his wife Kristin (IV4) had to be
This brings me to my own family. My father (1114)was left handed (rr:
and I, IV6, am also left-handed. a
This makes my mother, m113, carrier for the
gene (Rr). My sister IV5, is however unaffected. There was no information
available for my dad's side of the family being that he is deceased
My Aunt Dona (III5) married a left-handed man (III6). Neither of the
two sons, IV7 and IV8 that they had was effected however. Jefferey (IV8),
however has a son, Dylan, V6, who is left handed (rr). This means that Jetrs wife
Star (IV9), Jeff (IV8), my Aunt Donna (1115), and her son David (IV7) are all
carriers for the gene.
My Aunt Nancy, 1117,was also not affected with the left handedness.
Nancy however married a soft paw (rr). Blaine, 1118,had a son (IVIO) from a first
marriage who was left handed, however the child they had together, IVll, is not.
Given this information I would assume that my Aunt is not a carrier for this gene
and that she is RR but it isn't possible to know this information unless my cousin
Katie (IVll) marries a right handed man who is not a carrier (RR) and they have
no affected offspring. All would be genotype RR.
My Aunt Peg (1119)has two children (IV12 and IV13) and neither child is
affected with the gene. There is not much I can assume from this however
because little information was available to me about the children's fathers. My
Uncle Don (11113) has not produced any offspring to this point in his life so
whether he is of the genotype RR or Rr in not known.
I believe that the trait of being left-handed is Autosomal Recessive. I believe this
because many of the left-handed people in my family have parents who are right handed.
Both males and females in my family seem to share in the passing of the trait from one
generation to the next. This therefore rules out the possibility of it being a y-Iinked trait
or a sex influenced trait
I ruled out the possibility of this being an Autosomal Dominant trait because if
this were the case an affected person must always have an affected parent. There are
only three cases where this is true in my family and 3 cases were this is not. Also a
person who is not left-handed can not passthe trait on if this were the case. It is quite
obvious from my pedigree that this is not the case.