Transcript 7 4 Pedigrees and Karyotypes

Happy
Wednesday!!!
Patterns in humans follow other
11/9/2011
organisms!!!
Let’s have a SUPER day!
Opener question:
Please tell me the
difference between
incomplete dominance and
codominance!!
Give an example of each.
7.4 KEY CONCEPT
A combination of methods is used to study human
genetics.
Patterns in humans follow other
organisms!!!
• The basic principles of genetics are
the same in all sexually reproducing
organisms.
– Inheritance of many human traits is
complex.
– Single-gene traits are important in
understanding human genetics.
Sex-linked disorders!!!
• More common
than females,
no 2nd X to
mask it!!!
• XAY = normal
• XaY= has disorder
• No carriers!
• Only evident
when both
alleles are
present!
• XAXA = normal
• XAXa = carrier
• XaXa = has disorder
Females can carry sex-linked
genetic disorders but males
can’t!
• Males (XY) express
all of their X-linked
genes.
• WHY?????
• SO  NO MALE HETEROZYGOTES!
Y
X
Tracing genes in families!!
Phenotypes used to infer genotypes!!
PEDIGREE CHARTS
• P’types used to infer genotypes.
• Autosomal genes show different patterns on a pedigree
than sex-linked genes.
•Equal # males & females w/trait
•Recessive pheno …must be hom
recessive!!
•dominant pheno = hom dom or
hetero
•Either genotype can pass trait
•More M than F have rec pheno
•Female carriers = heterozygous
• can pass on trait
•Males w/ rec pheno can only pass onto
female offspring!
Check this out! What is happening from
one generation to the next???
a picture of all chromosomes in a
cell.
XY
– Extra or missing part of chrom.
– Extra or missing ENTIRE chrom.
– Genes missing, extra copies of genes…
XY
• Lab Area
• Look at your family history surveys
– DRAW on the sheet…
• Arrange them with
– Grandparents = GENERATION I
–
Parents = GENERATION II
– You, siblings = GENERATION III
• Make connection lines for marriages, etc.
• HIGHLIGHT ONE TRAIT…asthma, etc.
• Complete the questions!
• Whole family tree; Generation #s; legend/key; every person
is blank/filled/?.
The gene for this particular genetic trait does not occur on the sex chromosomes; it occurs on an
autosomal chromosome because both males and females have the trait. This information can be
inferred from two facts:
(1) Because the father has the trait, if the trait were sex-linked (on the father’s X chromosome),
then all females would have the trait. However, because some females do not have the trait, it is not a
sex-linked trait.
(2) Individual III-7 who (male) didn’t inherit the trait from his mom, who has the trait. He received
his only X chromosome from his mother.
This particular gene is a dominant gene because
○ each of the people who have the trait has only one parent who has the trait.
○ if only one parent has the trait and the trait is not sex-linked, then the individuals who have the
trait must be heterozygous for the gene.
DRAGON LAB!
• ONE PARTNER (PAIRS)
• DRAGON BABIES!
• FLIP THE STICKS…WE’LL DO ONE TOGETHER
• COLLECT THE DATA NOW, THEN WE’LL COME
BACK TO IT LATER TODAY.
DRAGON
LAB!
• Finish Up!
• DRAW your DRAGON
BABY!
Activity for Wed:
Karyotype of Self & Partner…
Song is on youtube…try this next time!
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The Ultimate Pedigree Challenge
Is it possible for someone to be his own grandpa? This story is actually a song written by Dwight Latham and Moe Jaffe (1947,
General Music Publishing Company, Inc.) Read the story (sing along if you dare) and draw the pedigree of this man's family. GOOD
LUCK!
Many, many years ago when I was twenty-three
I was married to a widow who was pretty as could be.
This widow had a grown-up daughter who had hair of red.
My father fell in love with her and soon the two were wed.
This made my dad my son-in-law and changed my very life
For my daughter was my mother, 'cause she was my father's wife.
To complicate the matter even though it brought me joy
I soon became the father of a bouncing baby boy.
My little baby then became a brother-in-law to dad
And so he became my uncle though it made me very sad
For if he is my uncle then that also makes him brother,
To the widow's lovely daughter who, of course, was my step-mother.
Father's wife then had a child which kept them on the run,
And he became my grandchild, 'cause he was my daughter's son;
My wife she is my mother's mother and it makes me blue,
Because although she is my wife, she's my grandmother too.
Now if she is my grandmother than I'm her grandchild
And every time I think of it, it nearly drives me wild;
For now I have become the strangest case you ever saw
As husband of my grandmother I am my own grandpa.
Chorus:
Oh, I'm my own grandpa, I'm my own grandpa
It sounds funny, I know, but it really is so
Oh, I'm my own grandpa.
Possible Solution!
Return to Ultimate Pedigree Challenge