RD INTERNATIONAL SCHOOL, ERODE
BIOLOGY INVESTIGSTORY PROJECT
PEDIGREE ANALYSIS OF
GENETIC TRAITS
GUIDED BY: MRS.MERCY CHANDRA BAI, PGT
[BIOLOGY]
DONE BY: PAARI.D.K [XII-D]
RD INTERNATIONAL SCHOOL, ERODE
BIOLOGY INVESTIGSTORY PROJECT
PEDIGREE ANALYSIS OF
GENETIC TRAITS
GUIDED BY: MRS.MERCY CHANDRA BAI, PGT
[BIOLOGY]
DONE BY: PAARI.D.K [XII-D]
CERTIFICATE
This is to certify that the project entitled “PEDIGREE
ANALYSIS OF GENETIC TRAITS” is a record of bonafide work
carried out by “PAARI.D.K” of “XII-D” in partial fulfilment of
the requirements in BIOLOGY prescribed by CBSE for 2023-
2024 in the school RD INTERNATIONAL SCHOOL,
GATEPUDHUR, ERODE.
DATE:
PLACE: PRINCIPAL
INTERNAL EXAMINER EXTERNAL EXAMINAR
ACKNOWLEDGEMENT
We wish to express our sincere thanks to our beloved
Founder Chairman Dr.D.SENTHIL KUMAR, our Chairman
Mr.S.RAGHUL, our Principal Mr.R.SHANKAR and our institution RD
International School, Erode for guiding and providing facilities
towards the successful outcome of this project work.
We wish to express our deep and profound sense of gratitude
to our guide teacher Mrs.MERCY CHANDRA BAI, PGT (BIOLOGY), for
her expert help, valuable guidance, comments and suggestions.
I express my heartfelt gratitude to my parents for constant
encouragement while carrying out this project.
We also express our sincere gratitude to one and all who
directly or indirectly, have lent their helping hand in this venture.
PEDIGREE ANALYSIS OF
GENETIC TRAITS
Table of contents
S.NO TOPICS
1 AIM
2 WHY THIS TOPIC?
3 INTRODUCTION
4 EXPERIMENT 1
5 CASE 1
6 CONCLUSION
7 EXPERIMENT 2
8 CASE 2
9 CONCLUSION
10 EXPERIMENT 3
11 CASE 3
12 CONCLUSION
13 WHAT WE LEARNT?
14 GALLERY
15 BIBLOGRAPHY
AIM:
To study the prepared pedigree charts of genetic traits such
as rolling of tongue, widow’s peak, attached or free ear lobe.
WHY THIS TOPIC?
I am interested in understanding ourselves in a better way.
As a branch of genetics, human genetics concerns itself
with what most of us consider to be the most interesting
species on earth; humans. It is also important to know how
we are different from each other.
INTRODUCTION
Genetics is a branch of biology concerned with the study of
genes, genetic variation and heredity in organism. Though
heredity has been observed for millennia, Gregor Mendel,
a scientist working in the 19th century, was the first to study
genetics scientifically. Mendel studied ‘trait inheritance’,
patterns in the way traits are handed down from parents to
offspring. He observed that organisms (pea plants) inherit
traits by way of discrete units of inheritance. This term, still
used today, is a somewhat ambiguous definition of what is
referred to as gene.
Trait inheritance and molecular inheritance mechanisms of
genes are still primary principles of genetics in the 21 st, but
the modern genetics has expanded beyond inheritance for
studying the function and behavior of genes.
EXPERIMENT 1
To study about the rolling of tongue as a genetic trait.
ROLLING OF TONGUE
Tongue rolling is the ability to roll the lateral edges of the
tongue upwards into a tube.
The tongues intrinsic muscles allow some people to
form their tongues into specific shapes.
Popular beliefs holds that variation in this ability is the
result of genetic inheritance.
Rolling of tongue into a tube shape is often described
as a dominant trait with simple Mendelian inheritance,
and it is commonly referenced in introductory and
genetic biology courses.
CASE 1
A father cannot roll his tongue but a mother can roll her
tongue. Among their four children one daughter cannot roll
her tongue but other daughter and two sons can roll their
tongue.
PUNNETT SQUARE
COLLECTION OF DATA
S.NO NAME ROLLING OF TONGUE
1 Ravi Yes
2 Lokesh Yes
3 Kumar No
4 Rathna Yes
5 Jagadish No
6 Vikram Yes
7 Vasanth Yes
8 Sriram No
CONCLUSION
The trait is present in the father parent due to presence of
two recessive genes (aa). The trait can appear in progeny
only when it becomes heterozygous recessive. Since, only
one of the progeny carries the trait, the mother parent must
be heterozygous (Aa). Cross between the father and
mother produces one homozygous recessive progeny.
EXPERIMENT 2
To study about widow’s peak as a genetic trait.
WIDOW’S PEAK
A widow’s peak is a V-shaped point in the hairline in the
center of the forehead. Hair growth on the forehead is
suppressed in a bilateral pair of periorbital fields. Without a
widow’s peak, these fields join in the middle of the forehead
so as to give a hairline that runs straight across. A widow’s
peak results when the point of intersection on the forehead
of the upper perimeters of these fields is lower than usual.
CASE 2
Father has widow’s peak hairline and the mother has
straight hairline. The hairlines among their progenies will
be:
PUNNETT SQUARE
WW – Widow’s Peak
Ww – Widow’s Peak
ww - Straight
CONCLUSION
Father is homozygous dominant while the mother is
homozygous recessive. In second generation all progeny
will be heterozygous (Aa). Further in third generation 75%
of the progeny will have straight hairline and 25% of the
progeny will have widow’s peak hairline.
EXPERIMENT 3
To study the ear lobes as a genetic trait.
EAR LOBE
The human earlobe is composed of tough areolar and
adipose connective tissues, lacking the firmness and
elasticity of the rest of the auricle (the external structure of
the ear). In some cases the lower ear lobe is connected to
the side of the face.
Since the earlobe does not contain cartilage it has a large
blood supply and may help to warm the ears and maintain
balance.
However, earlobes are not generally considered to have
any major biological function. The earlobe contains many
nerve endings, and for some people it is an erogenous
zone.
CASE 3
Father has attached earlobe and mother has free earlobe.
The earlobes of their progenies will be:
PUNNETT SQUARE
s.no name earlobes
1 Vijay Free
2 Ajay Free
3 Karthick Free
4 Vikram Free
5 Amar Attached
6 Rakesh Free
7 Kumar Attached
8 Rathna Attached
9 Jagadish Free
10 Parthiban Free
CONCLUSION
Free earlobes are dominant over attached earlobes. Father
is homozygous recessive and mother is heterozygous
dominant. After mating 50% of the progeny will bear
attached earlobe and 50% of the progeny will bear free
earlobe.
GALLERY
STRAIGHT TONGUE ROLLED TONGUE
WIDOW’S PEAK HAIRLINE STRAIGHT HAIRLINE
ATTACHED EARLOBE FREE EARLOBE
BIBLIOGRAPHY
NCERT Class 12 textbook
www.wikipedia.com
www.sciencedirect.com
www.cribd.com
