The document discusses Mendelian and non-Mendelian inheritance, explaining Mendel's laws of segregation, independent assortment, and dominance. It then provides examples of non-Mendelian inheritance including codominance seen in flower color, incomplete dominance in snapdragon flower color, and multiple alleles determining coat color in rabbits and blood type in humans. Activities are suggested to have students apply these genetics concepts.

1. Modifications to
Mendel's Classic
Ratios
General Biology II
Jose Amado Ds. Torreda

2. Mendelian Inheritance
-it is a type of biological inheritance that
follows the laws of Gregor Mendel.
These laws are the:
• Law of Segregation
• Law of Independent Assortment
• Law of Dominance
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3. Mendelian Inheritance
Law of Segregation
-during gamete formation, the alleles for
each gene segregates from each other so
that each gamete only carries ONE allele for
each gene.
Aa= 50% A, 50%a
AA= 100% A
aa= 100%a
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4. Mendelian Inheritance
Law of Independent Assortment
-genes for different traits can segregate
independently during the formation of
gametes.
AaBb= AB, Ab, aB, ab
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5. non-Mendelian Inheritance
-not all traits follow the Mendelian mode of
inheritance
-it is when a trait doesn't follow any of the Laws
of Mendel.
Examples of non-Mendelian Inheritance
1. Co-dominance
2. Incomplete dominance
3. Multiple alleles
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6. non-Mendelian Inheritance
1. Co-dominance
-when two contrasting alleles are present in
the same locus or trait (heterozygous genotype),
both alleles are simultaneously expressed.
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7. non-Mendelian Inheritance
Example of co-dominance
CR
=red flower
CW
=white flower
CW
CW
x CR
CR
= CW
CR
note that we didn't
use “r” or “w”
because neither the
red or the white
is recessive.
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8. non-Mendelian Inheritance
Example of co-dominance
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9. non-Mendelian Inheritance
Example of co-dominance
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10. non-Mendelian Inheritance
2. Incomplete dominance
-when two contrasting alleles are present in
the same locus or trait (heterozygous genotype),
the phenotype expressed is a “blend” of the two
extreme phenotypes.
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11. non-Mendelian Inheritance
Example of incomplete dominance
In the snapdragon, Antirrhinum majus, a cross
between a homozygous white-flowered plant
(CW
CW
) and a homozygous red-flowered plant (CR
CR
)
will produce offspring with pink flowers (CW
CR
)
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12. non-Mendelian Inheritance
Example of incomplete dominance
The Snapdragon (Antirrhinum majus)
12

13. non-Mendelian Inheritance
3. Multiple alleles
-when there are more than two types of
alleles for a given locus or trait, this will result in
more than two kinds of phenotypes that may be
expressed for that trait.
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14. non-Mendelian Inheritance
Example of multiple allele
1. Coat color in rabbits
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15. non-Mendelian Inheritance
Example of multiple allele (Ch
c=himalayan x Cch
c=
chinchilla)
1. Coat color in rabbits (C> Cch
> Ch
> c)
The following genotypes will have the corresponding
phenotypes in coat color:
i. CC – Agouti
ii. CCch
– Agouti
iii. CCh
– Agouti
iv. Cc – Agouti
v. Cch
Cch
– Chinchilla
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vi. Cch
Ch
– Chinchilla
vii. Cch
c – Chinchilla
viii.Ch
Ch
– Himalayan
ix. Ch
c – Himalayan
x. cc – Albino

16. non-Mendelian Inheritance
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Cch
c
Ch
Cch
Ch
chinchilla Ch
c himalayan
c Cch
c chinchilla cc albino
Example of multiple allele (Ch
c=himalayan x Cch
c=
chinchilla)

17. non-Mendelian Inheritance
Example of multiple allele
2. ABO blood typing in humans
-there are three different types of alleles IA
, IB
and i.
OO (Type O) x BO (Type B)
Blood types:
Type A= IA
IA
or IA
i
Type B= IB
IB
or IB
i
Type AB= IA
IB
Type O= ii
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18. non-Mendelian Inheritance
2. ABO blood typing in humans
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19. non-Mendelian Inheritance
2. ABO blood typing in humans
Universal RBC donor= O
Universal RBC recipient= AB
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20. non-Mendelian Inheritance
(Father)Type AB x (Mother) Type B= BO or BB
(Child) Type A (AO or AA)
1st
case: AB x BO
2nd
case: AB x BB
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B O
A AB AO
B BB BO
B B
A AB AB
B BB BB

21. Activities on non-Mendelian
Inheritance
1. Seatwork
Get the phenotypic ratio and the probability of
having a rabbit with a certain coat color from the
cross below.
CCch
x Cch
Ch
2. Exercise
3. Pedigree of your immediate family based on ABO
blood types.
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22. Exercise
A local hospital has sent word to a family of a possible mix
up of some of the children with other families when they
were born. To rule out any possible mix up, the hospital
obtained the blood types of every individual in the family,
including the surviving maternal grandfather and paternal
grandmother. The results were as follows:
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Father: Type O Mother: Type A
1st child: Type O 2nd child: Type A
3rd child: Type B Mom's father: Type AB
Dad's mother: Type B