Heredity
Remember that genes are segments of DNA that carry instructions
for the ______________ of an organism. When organisms
reproduce, genetic information from each ________________ is
passed to the next generation. This passing of traits to the next
generation is called heredity. Traits like height, weight, and the
shape of your body and face are traits that are inherited but are also
greatly influenced and changed by your ___________________.
For example, your diet, state of health, and the amount of
_______________ you get can change your body size and
appearance.
How Much of Our DNA is the Same as other Organisms
We share over __________ of our genetics with even very
primitive animals like insects and fish. A cow shares
approximately 80% of the same DNA on genes as humans. The
animal that is closest genetically to humans is the
__________________; we share 98.8% percent of our DNA with
them. Our closest extinct animal is the Neanderthal man in which
we share _______ percent of our DNA. We share with other
_________ about 99.9% of our DNA. Remember that our genes
are like switches that turn _____or ________. Some
___________ turn on, others are always ___________, and still
others turn _______ and _________.
(Neanderthal – Cro-Magnon, Modern Humans)
Everyone in the classroom has some Neanderthal DNA about 1 to 3 percent. The maximum
Neanderthal DNA possible is approximately 6 percent. Every human owes a debt to
Neanderthal DNA as the gene that produces our immune system comes from Neanderthal
DNA. The immune system is the body's defense against infectious organisms and other
invaders.
Allele
Every organism has a ____________ of genes that determine its
traits.
Each gene in a pair is known as an allele.
Types of Alleles – Dominant and Recessive
Parents with brown eyes can have children with blue eyes.
Scientists have found that parents can carry hidden
_____________. The gene for a certain trait is there, but the trait
does not ____________ itself.
If one of the alleles masks the effect of the other allele, it is called
a ______________________ allele.
The allele that is masked or hidden is called a
___________________ allele.
The dominant allele is always written with a ________________
letter such as “T” for tallness. The recessive allele for the same
trait is written with a lowercase version of the __________ letter.
The trait for shortness would be written as “___”.
Parents and children do not look exactly __________; as a child
inherits __________ allele (one gene for each trait) from each
___________________. Sometimes an organism inherits dominant
alleles or two recessive alleles for a ___________. When this
happens, the organism ______________ the trait carried by the
alleles. An example is if a pea plant has two alleles for tallness
(the dominant trait) it will be __________ (______). If the pea
plant has two alleles for shortness (the recessive traits) it will be
_______________ (______). An organism that carries two
dominant or recessive alleles for a given trait is said to be pure or
homozygous for that ___________________.
Sometimes an organism can inherit a dominant allele and a
recessive allele for the same trait. When this happens the dominant
allele ________________the effect of the recessive allele. For an
example if a pea plant inherits an allele for shortness from one
parent and an allele for tallness from the other parent then the
offspring will be _________________ and carry one allele for
tallness and one allele for shortness (_____).An organism that
carries both a ______________ allele and a _________________
allele for a certain trait is called a hybrid or heterozygous. The
dominant allele is always written before the recessive allele in a
trait that is heterozygous. The advantage in being heterozygous is
in genetic ________________ such as sickle cell anemia where
humans who are homozygotic for sickle shaped cells (pictured
below) suffer from a near lethal condition.
There are, however, times when neither allele for a trait is
_________________ or_________________. In this case
both alleles instruct the organism to do “something.” One
classic example is that in many flowering plants such as
roses, snapdragons, and hibiscus, there is a gene for flower
color with ___________ alleles: red and white. However, in
that case, white is not merely the absence of red, but that
allele actually instructs the flower to “make white pigment.”
The red allele instructs the flower to “make red pigment”
Thus the flowers on a plant that have two sets of instructions:
“make _________,” and “make_____________,” will have
the result that the flowers turn out mid-way in between;
they’re ________________. When neither of the two alleles
is dominant or recessive, it is called incomplete dominance.
http://www.youtube.com/watch?v=Mehz7tCxjSE Mendal
http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html
human evolution