Genetics & Heredity
Stand up for
Candy!
Genetics & Heredity
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Heredity or Environment?

Color of hair
 Color of eyes
 Color of Skin
 General health
 Personality traits
 Strength of eyesight
 Physical strength
 IQ
 Height

Relationship with family
 Relationship with friends
 Level of education
 Sex
 Body Type
 Weight
 Religious involvement
 Birth Defects
 Blood Type
How do we get our genetics?
When are heredity traits determined?
At conception

Through Genes and
Chromosomes…..Wh
at are the difference
between the 2??
Which one holds our
DNA?
Chromosomes
A.
Chromosomes are rod
shaped chemical
compounds that carry
genetic coding.
B. The genetic coding
transmits characteristics
from the parent to the
child.
Chromosomes
C.
Found in both sperm and ovum
D.
Every cell has 23 pairs of chromosomes, 46
total
E.
Sperm and ovum contain 23 chromosomes
each.
Genes
A. They are the
building blocks of
chromosomes.
B. They are bead-like
structures.
Genes
C, There are hundreds of
genes on each
chromosome.
D. They carry individual,
specific traits.
Genes
E. They can be
dominant
(stronger) genes
which produce
the characteristic
in the individual
Blue Eyes
Genes
F. They can be
recessive (weaker)
genes which do not
produce the
characteristic unless
transmitted by both
parents.
Red Hair
Study Guide T/F Questions

T The
1. _______
passing on of traits
from parent to child is
called heredity.
Environmental
influences are the
surroundings that we
are placed in.

READ The Scenario: Sammy has brown eyes
and is five years old. She attends a neighborhood
preschool every day. Her teachers have fallen in
love with her witty personality and honey-colored
hair. She is very intelligent and does well with the
tasks assigned to her. Sammy’s parents are
divorced and she misses her father very much.
Sammy has juvenile arthritis and must see the
doctor often. At her last doctor’s visit, the doctor
reminded Sammy’s mom that diabetes has run in
her family for several generations and that Sammy
should be watched closely for any early symptoms
of diabetes. Sammy’s growth chart shows that she
will probably be small for her age.
List the Heredity Influences in the above scenario:
List the Environmental Influences in the above
scenario:
T Genes carry
 2. _______
inherited traits that are
passed on from
generations to
generations. Hundreds of
thousands of genes,
which make up the traits
of human beings, are
carried on every
chromosome.

F
3. ________Heredity
influences such
personal aspects as
eye color, personality,
and food preference.

T Dominant
4. _______
genes are stronger
genes and recessive
genes are weaker.
Dominant=Strong
Recessive=Weak


DOMINANT
Brown hair
Other Color hair
Brown eyes
Straight hair line
Free Earlobes
Roll Tongue
Second finger shorter then the 4th
T
5. _______
In the
formation of a new
individual where the
genes are both
Hitchhiker’s thumb
recessive and
 RECESSIVE
dominant, the
Blonde hair
dominant will
Red hair
Blue Eyes
overpower.
Widows peak
Attached earlobes
Can’t roll tongue
Interlock hands and right thumb on top
No hitchhiker’s thumb
Dominant vs. Recessive
a.
widow’s peak
a.
b.
Unattached earlobe
a.
c.
Attached earlobe
Short fingers
a.
d.
Continuous hairline
Long fingers
Freckles
a.
Lack of freckles
T It is
6. _______
probable that a
dominant brown-eyed
mother and a
recessive blue-eyed
father will have a
brown-eyed child.
Determine the chances of passing on a genetic trait in the
following situation:

The wife is blue-eyed and carries genes for blue eyes on
both of the chromosome pairs. The husband is brown
eyed and carries a gene for brown eyes on one of the
pairs and a gene for blue eyes on he other one of the
pairs. Complete the following grid to determine the
chances for each of their children to be born with blue or
brown eyes.
B = dominant brown gene b = recessive blue gene

There is a _____________________ in four chance that
the child will have brown eyes and carry a gene for blue
eyes.

There is a _____________________ in four chance that
the child will have blue eyes and carry genes for only
blue eyes.
Wife b
Husband
B
Husband
b
Wife b
Bb
Bb
bb
bb

T
7. _______
It is
probable that a child
can have recessive
light colored hair even
though both of his
parents have
dominant dark
colored hair.
What is a carrier:
A person who is able
to pass a particular
trait onto his/her own
child even though the
trait has not been
expressed in him/her
Red Hair and blue –green eyes
Recessive (weaker)
genes will not
produce the
characteristic unless
transmitted by both
parents.

F The
8. _______
female sex cell is the
ovum with XY
chromosomes and
the male sex cell is
the sperm with XX
chromosomes.
XX
XY

F Each
9. _______
sperm cell and ovum
cell carries 23
chromosomes and
when the ovum is
fertilized, the sex cell
equals 46Chromosomes.
new eyes.

T 50% of
10. _______
the chromosomes
come from the father,
but he determines the
sex of the child.
XY Boy or XX Girl?

F
11. _______
Twitterpation
Conception is the
union of an ovum and
a sperm or the
beginning of
pregnancy.
MULTIPLE BIRTHS

F
12. _______
Fraternal
non-identical multiple
births that come from
two different eggs will
like siblings.
look identical
.
Dizygotic- is the
scientific name for nonidentical multiple
births, which means
coming from two
fertilized eggs.
F Identical
13. _______
multiple births that
come from one
fertilized egg
can
will be
be the
different
samesexes.
sex.

Monozygotic- scientific name for identical multiple births, which means coming from
one fertilized egg.
TRIPLETS
* Triplets can occur through
several combinations. Three
separate ovum could be released
and fertilized.
* Two ovum could be released,
fertilized and then one ovum
splits into separate embryo,
resulting in a set of identical
twins and one fraternal twin.
* One ovum could split into three
parts resulting in identical
triplets
F
14. _______
Double
Conjoined
jointed
twins
twins
are when the ovum splits
apart but the separation
is not complete.
CONJOINED TWINS
Conjoined twins result when
a fertilized ovum begins to
split into two parts, but does
not fully complete the
process. The babies are joined
at whatever location does
not complete the splitting
process.
????????

How many chromosomes are there in each
cell?
 46 CHROMOSOMES or 23 PAIRS

How many chromosomes are in
Reproductive (egg & sperm) or Germ cells?
 23 CHROMOSOMES

(combined = the 46 chromosomes)
 Female
Sex Cells XX
(Ovum or
Egg)
 Male
Sex Cells XY
(Sperm)
 Baby Girl = XX Baby Boy = XY

Conception is the union of an OVUM and the SPERM
 Gender

is determined by the father!
Someone should have told King Henry VIII!
 DOMINATE
Gene: More powerful - trait seen in
person
 RECESSIVE
Gene: Weaker and hides in the
background. Trait can only determine when two of them are
present - may show up in future generations.
 CARRIER:

SEX-LINKED: Mother passes the recessive X to son






Has a recessive gene that is not visible
Color-blind male receives the trait from his mother.
The mother is usually not color-blind herself.
B = BROWN eyes (dominate)
b = BLUE eyes
(recessive)
BB = BROWN eyes
bb = BLUE eyes
Bb = BROWN eyes but carry the recessive BLUE eye gene
MULTIPLE BIRTHS
 ZYGOT: the cell that is formed when a sperm fertilized
an egg (ovum)
 MONOZYGOT: Identical Twins 1 Egg + 1 Sperm

Fertilized ovum splits into 2 identical cells - Always the same
gender
 DIZYGOT: Fraternal Twins 2 Eggs + different Sperm


MULTIPLE BIRTHS: More than 2


Will look different - May be different or the same gender
May be identical, fraternal or both - May be different or the same
gender
CONJOINED (Siamese) TWINS: Ovum splits apart, but the
separation is not completed. Babies are joined at some part of their
bodies.
What 4 FACTORS may contribute to
Multiple Births?
 1)
History in the family
 2) Increased hormones naturally

 3)
Fertility Drugs

 4)

More than 1 egg released
More than 1 egg released
Age 32-36
Likelihood of multiple pregnancies in the United States

Twins: Blacks- 1 in 73
Whites 1 in 93

Triplets: 1 in 10,000

Quadruples: 1 in 620,000
Preview for defects….

Sex - Linked or X - Linked Defect: When an X-gene from
the mother is faulty. There is a 50/50 chance of the child inheriting the
disorder.

Syndrome: When a group of signs and symptoms occur together
and characterize a particular problem.

Congenital Malformation: A condition that is present at birth.
 Multi-factorial Defects: Interaction of genes with other genes
OR with environmental factors.

Chromosomal Error: The fertilized egg cell that contains
chromosomes in an abnormal number, structure or arrangement.
Complete the Genetic Gamble
Find a partner
You need a dice for
each pair
And a piece of paper
For each trait, flip or roll 2x to determine what gene will be
contributed to
the child’s facial features. Person #1 contributes a gene and Person #2
contributes a gene.
HEADS / EVENS = Dominant (capital) and TAILS / ODDS =
Recessive (lower case).
Record the genetic contribution of each person and identify the facial
characteristic it refers to.
Draw the “child” based upon the assigned facial characteristics.








HEADS / EVENS = Dominant (capital)
and TAILS / ODDS = Recessive
(lower case).
1- Hair color: Dark down or black (dominate) Blond
or red (recessive)
2-Eye Color: (Brown (dominate) Blue (recessive)
3-Dimples (dominate) no dimples (recessive)
4-Earlobes: Hang free (dominate) Attached
(recessive)
5-Widows Peak (Dominate) no widows peak
(recessive)
6-Tong Roller (Dominate) no roller (recessive)
7-Hand Writing: right (dominate) left (recessive)
8- Curly or straight hair: curly (Dominate) Straight
Draw your baby….









HEADS / EVENS = Dominant (capital)
and TAILS / ODDS = Recessive
(lower case).
R—Tongue roller: Ability to roll tongue into a Ushape (r—non-roller)
P—Widow’s peak: Hairline forms a distinct
downward point on forehead (p—no peak)
E—Earlobes: Earlobes hang free from the side of
the head (e—earlobes attached)
F—Straight little finger: Little finger can be pressed
to ring finger with no gap. (f—little finger bends in or
away from ring finger)
L—Long index finger: Index finger is longer than
ring finger. To find this trait, place index finger at the
edge of a piece of paper and compare ring finger’s
position to paper’s edge. (l—shorter index finger)
H—Dark hair: Brown or black hair (h—blonde or red
hair)
D—Dimples: Indentations in cheeks or chin (d—no
dimples)
W—Writing hand: Write with right hand (w—write
with left hand)
Y—Right dominant eye: Right eye sees the same
perspective as both eyes together. To find this trait,
look at an object through a rolled piece of paper
using both eyes. Then close one eye and then the
other. The object can still be seen in the same
perspective through the rolled paper only with the
dominant eye. (y— left dominant eye)