1. ASSIGNMENT TOPIC: PLEIOTROPY
NAME HAFIZ MUHAMMAD WASEEM
ROLL NO. MCF-1901171
SEMESTER 3ed(E)
DEPARTMENT ZOOLOGY
SUBJECT GENETICS
PRESENTED TO
MAM SAJIDA NASEEM
PRESENTED DATE 07-12-2020
2. CONTENTS
DEFINATION
HISTORY
EXAMPLE OF PLEIOTROPY
1. PHENYLEALKAPTANORIA OR PKU
2. THE FRIZZELED FEATHER TRAIT
3. SICKEL CELL
4. VESTIGIAL GENE IN FRUIT FLIES
5. DEAFNESS AND PEGMENTATION IN CATE
6. MARFAN SYNDROME
REFRENCES
3. DEFINATION• “ one gene controls for the expression of multiple phenotypic traits”. These traits
don’t have to be clearly linked, i.e., eye shape and eye color, but can instead be
completely unrelated.
• Old concept
• One gene ---------one trait(product
• One gene------------ more then one trait (gene controle more then one trait
Pleiotropic gene)
• Effect of gene is called pleiotropic effect
• Phenomena is called pleiotropy
4. HISTORY By Ludwing plate and published in
1910
Pleitropy was first noticed by
geneticist Gregor Mendel, who is
known for his famous studies with
pea plants. Mendel noticed that plant
flower color (white or purple) was
always related to the color of
the leaf axil (area on a plant stem
consisting of the angle between the
leaf and upper part of the stem)
and seed coat.
5. EXAMOLES OF PLEIOTROPY
1. PHENYLEKETONEUREA OR PKU
Phenylketonuria also called PKU, is a rare inherited disorder that causes an amino
acid called phenylalanine to build up in the body.
an enzyme needed to break down phenylalanine. Without the enzyme necessary to
process phenylalanine, a dangerous buildup can develop
a person with PKU eats foods that contain protein or eats aspartame, an artificial
sweetener.
2. Tyrosine-------melanie (albomine) skin pigmentation and hair
3. Mental retardation
6.
7.
8.
9. THE FEIZZELED FEATHER TRAIT
HISTORY
It was observed by Walter Landauer and Elizabeth Upham in 1963 that the chickens
that exhibit the dominant frizzle genes mostly produce feathers that curl on their
whole bodies instead of lying flat against their skin.
The KRT75 gene is considered as the dominant gene responsible for the frizzle trait
in several chicken breeds,
Chickens with this particular mutated feather gene display feathers that curl outward
as opposed to lying flat.
loss of body heat requiring a faster basal metabolism to maintain homeostasis.
faster metabolism
higher food consumption,
enlarged organs.
infertility,
and sexual maturation delays.
10. CONCLOSION
A deletion in the KRT75L4 gene is responsible for the frizzle feather phenotype in
the Kirin chicken.
The identification of this mutation, which causes a developmental defect of avian
integument appendages, will improve our understanding of the mechanisms that are
involved in feather formation.
11. SICKLE CELL ANEMIA
HISTORY
Dr. Earnest E. Irons, the intern who was on duty that day, performed a routine blood
test and a urine analysis for Noel and was the first to observed these “pear shaped,
elongated” sickled blood cells.
Sickel shape cells
Sickle cell is a result of a mutation in the beta-globin gene.
The results in red blood cells sickle-shaped, which causes them to clump together
and become stuck in blood vessels, blocking normal blood
Heme contains iron and gives a red color to the molecule.
Globin consists of two linked pairs of polypeptide chains.
12.
13. CROSS BETWEEN TWO SICKEL CELL
CARRIER
• Thus a marriage between 2 sickle cell anemic
carriers produces 1 normal, 2 sickle cell
carriers and 1 sickle cell anemic children in the
ratio 1:2:1.
• But as the anemic child dies the ratio of sickle
cell carriers and normal becomes 2:1.
16. MECHANISMS
HbS sticks together
Forms long rods form inside RBC
RBC become rigid, inflexible, and sickle-shaped
blocks small blood vessels
Less oxygen to tissues of body
RBCs containing HbS have a shorter lifespan
Normally 20 days
Chronic state of anemia
21. THE VESTIGIAL GENE IN FRUIT FLIES
Role in the development of the wing of the drosophila,
short wings
unable to fly
Homozygous for the recessive form of the vestigial gene (vg).
Reduced numbers of eggs present in the ovaries of the flies,
Change in the places of the bristles on the scutellum of the flies,
Reduced time span of the life cycle of the flies
23. DEAFNESS AND PEGMENTATION IN CATES
Around forty percent of cats that exhibit white fur
and blue eyes are found to be deaf.
White cats that have one blue eye and another yellow
eye were blind from the one eye and that was mostly
the blue eye but later one it was seen that this
phenomenon of blindness
It is not always valid to all breeds of the cats.
25. MARFAN SYNDROME
The inherited disorder that results in the connectivity issues in the
tissues is called the marfan syndrome.
This syndrome affects the eyes, heart, skeleton, and blood vessels.
Long heightened, thin bodies with long legs, arms, fingers, and toes
Aortic aneurysm, aortic dissection, and valve malformations are the
results of cardiovascular complications.
On the other hand, eye complications, lens dislocations, retinal
problems, and early-onset glaucoma also known as cataracts are very
important. .
28. REFERENCES
1.”Pleiotropy and lethal alleles”. (2018). Khanacademy.org.
2. Muskopf, S. (2020). “Genetics- Lop Ears”. Biologycorner.com,
2020.
3. Rajaratnam, R., Sunquist, M., Rajaratnam, L. and Ambu, L. (2007).
“Diet and habitat selection of the leopard cat (Prionailurus
bengalensis borneoensis) in an agricultural landscape in Sabah,
Malaysian Borneo”. 23,2: 209-217, 2007.
4. Ramirez, F. and De Backer, J. ( 2019). “Marfan Syndrome”. Human
Pathobiochemistry: Springer. pp. 241-254.
5. Bailey, R. (2019). “What is Pleiotropy? Definition and Examples”.
Thoughtco.com
Brooker, R. J. (2017). Genetics: Analysis and Principles. McGraw-
Hill Higher Education, New York,
