Genetics-4.pptx - Parrott

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14 Δεκ 2012 (πριν από 4 χρόνια και 7 μήνες)

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Genetics
-
4.3.12,10.3.1,10.
3.2

David Barkley

Taylor Turner

Polygenic Inheritance


Polygenic inheritance is the inheritance of
a characteristic that is controlled by more
than one gene.


Human traits that show continuous
variation include weight, height and skin
color.


P
olygenic
I
nheritance


This means that something simple, like skin
color, is affected by more than one gene
from ones parents. Each allele of a
polygenic character will offer a little bit of
information to the whole phenotype.


Polygenic Inheritance


Human skin color is a good example to
visually see how more than one gene can
affect appearance.


Polygenic Inheritance


In humans there are at
least three genes
coding for skin color.
Each skin color gene
has two forms; one
form codes for high
levels of melanin
production, and the
other form codes for
low levels of melanin
production

Polygenic Inheritance


Wheat


Kernel color in wheat is determined
by two gene pairs


crossing individuals with the
phenotype extremes yield offspring
that are a 'blend' of the two parents

Polygenic Inheritance


When these homozygotes are crossed the
offspring are all double heterozygotes
AaBb


two double heterozygotes are crossed
-
http://staff.jccc.net/pdecell/evolution/pol
ygen.html

4.3.12
Deduce
the genotypes
and
phenotypes of
individuals in
pedigree
charts.

Pedigrees:


Are used to illustrate the mode of
inheritance (dominant or recessive)


Give clues
to the mode of inheritance of
the
disease


Show potential threat
to other family
members


Phenotypes:


Observable and measurable charaterics
in an organisms


Effects of genetic coding and
environment

Ex:



eye color


Genotypes:


Genetic composition of organisms


With respect to the specific traits they describe


Refers specifically to genetic code (environment
has no effect)


Type of
Inheritance

Autosomal Dominant Inheritance


Requires only one parent to
carry the dominant gene in
order for children to be
affected.


Autosomal Recessive
Inheritance


Requires for both parents must
carry the recessive gene for
offspring to be affected.

X
-
Linked Dominant & Recessive
Inheritance


More common in boys because they only
need one gene



A mother gives the dominant or recessive
gene male offspring and the father gives
the Y chromosome.


Pedigree Vs. Punnett Square


A punnett square is used to determine the
out come of two alleles being crossed



Contrarily a pedigree is used to find
modes of inheritance for genetic diseases

Extra Pedigree Practice


www.zerobio.com
/drag_gr11/
pedigree
/
p
edigree
_overview.htm

I’M MY OWN
GRANDPA

Works Cited


" 10.3.2 Explain that polygenic inheritance can contribute to continuous variation using two
examples, one of which must be human skin color. ."
ARHicks â

” Just another Edublogs.org
weblog
. N.p., n.d. Web. 9 Feb. 2012. <http://arhicks.edublogs.org/2011/06/07/10
-
3
-
2
-
explain
-
that
-
polygenic
-
inheritance
-
can
-
contribute
-
to
-
continuous
-
variation
-
using
-
two
-
examples
-
one
-
of
-
which
-
must
-
be
-
human
-
skin
-
color/>.


"Define polygenic inheritance
-

IB Biology Syllabus."
IB Biology Syllabus Home
-

IB Biology
Syllabus
. N.p., n.d. Web. 9 Feb. 2012.
<http://ibbiology.wetpaint.com/page/Define+polygenic+inheritance>.


"Explain that polygenic inheritance can contribute to continuous variation
-

IB Biology
Syllabus."
IB Biology Syllabus Home
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IB Biology Syllabus
. N.p., n.d. Web. 9 Feb. 2012.
<http://ibbiology.wetpaint.com/page/Explain+that+polygenic+inheritance+can+contribute
+to+continuous+variation>.


"Gene Interactions."
Estrella Mountain Community College
. N.p., n.d. Web. 9 Feb. 2012.
<http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookgeninteract.html>.


"Genetic engineering and biotechnology."
IB Guides
. N.p., n.d. Web. 12 Feb. 2009.
<www.ibguides.com/biology/notes/genetic
-
engineering
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and
-
biotechnology>.


"IB Biology Syllabus."
Biology for Life
. N.p., n.d. Web. 9 Feb. 2012.
<http://www.biologyforlife.com/course%20info/Syllabus/Syllabus.htm#Topic_10:__HL_Geneti
cs>.


"Polygenic inheritance."
JCCC Staff and Faculty Pages
. N.p., n.d. Web. 13 Feb. 2012.
<http://staff.jccc.net/pdecell/evolution/polygen.html>.