HAJRAH ALI – 40157986
UXBRIDGE COLLEGE
UNIT 11: GENETICS AND GENETIC ENGINEERING LEARNING AIM C:
EXPLORE THE PRINCIPLES OF INHERITANCE AND THEIR APPLICATION IN PREDICTING GENETIC TRAITS
HUMAN INHERITANCE AND PREDICTING GENETIC TRAITS
VOCATIONAL SCENARIO:
As a trainee lab technician working for a medical research company, you must be able to predict patterns of
inheritance and analyse correlations between expected and observed results. Your company offer work placements
for the sixth form students. You have been asked to help the sixth form students understand how an expected ratio
of inheritance can be different to an observed ratio and how statistical tests can determine if this difference is
significant, caused by something or if it is just due to chance.
, C.M5 APPLY MENDEL’S LAWS OF INHERITANCE TO THE RESULTS OF GENETIC CROSSES.
MENDEL’S LAW
Johann Gregor Mendel (1822-1884) had made many observations through carrying out experiments in his garden his
known experiment was known for his work on pea plants and had discovered the basic principles of heredity. His work
became the foundation of modern genetics and the study of heredity.
The conclusion made was that the traits were specified by “heritable elements” called genes. Genes are expressed
through alleles, dominant and recessive. Each individual has two alleles for each gene, one from each parent made of
genotype or phenotype.
PISUM SATIVUM
Once Mendel had made discovery on true-breeding pea, he began to investigate how the traits were inherited by
carrying
out a series of crosses.
He crossed a pure breeding parent to another and called it the P generation.
Collected seeds from the P generation and grew them. These offspring were called F 1 generation.
(PP X pp) 100% of the offspring were of the dominant trait (Pp).
He let the F1 generation self-fertilise naturally which he the collected the seed of producing the F 2 generation.
(Pp X Pp) produces offspring with a 3:1 ratio.
Each time he produced a generation he recorded and examined their traits. (F 1,F2,F3, and F4)
MONOHYBRID INHERITANCE: Is the inheritance of a characteristic controlled by a single gene.
EXAMPLE: Mendel’s Pea plants.
POSSIBILITIES
If the parents were heterozygous: 3:1 purple: yellow
If the parents were PP and pp: 100% purple
If the parents were Pp and pp: 2:2 , 1:1 , 50%
If the parents were Pp and PP: 100% purple
T = tall
t = short
F1 GENERATION
PARENTS PHENOTYPE TALL SHORT
PARENTAL GENOTYPE TT Tt
GAMETES TT tt
CROSS T T
t Tt Tt
t Tt Tt
OFFSPRING GENOTYPES All Tt
OFFSPRING PHENOTYPES All tall – 100% Tall
F2 GENERATION
PARENTS PHENOTYPE TALL TALL
PARENTAL GENOTYPE Tt Tt
GAMETES Tt Tt
UXBRIDGE COLLEGE
UNIT 11: GENETICS AND GENETIC ENGINEERING LEARNING AIM C:
EXPLORE THE PRINCIPLES OF INHERITANCE AND THEIR APPLICATION IN PREDICTING GENETIC TRAITS
HUMAN INHERITANCE AND PREDICTING GENETIC TRAITS
VOCATIONAL SCENARIO:
As a trainee lab technician working for a medical research company, you must be able to predict patterns of
inheritance and analyse correlations between expected and observed results. Your company offer work placements
for the sixth form students. You have been asked to help the sixth form students understand how an expected ratio
of inheritance can be different to an observed ratio and how statistical tests can determine if this difference is
significant, caused by something or if it is just due to chance.
, C.M5 APPLY MENDEL’S LAWS OF INHERITANCE TO THE RESULTS OF GENETIC CROSSES.
MENDEL’S LAW
Johann Gregor Mendel (1822-1884) had made many observations through carrying out experiments in his garden his
known experiment was known for his work on pea plants and had discovered the basic principles of heredity. His work
became the foundation of modern genetics and the study of heredity.
The conclusion made was that the traits were specified by “heritable elements” called genes. Genes are expressed
through alleles, dominant and recessive. Each individual has two alleles for each gene, one from each parent made of
genotype or phenotype.
PISUM SATIVUM
Once Mendel had made discovery on true-breeding pea, he began to investigate how the traits were inherited by
carrying
out a series of crosses.
He crossed a pure breeding parent to another and called it the P generation.
Collected seeds from the P generation and grew them. These offspring were called F 1 generation.
(PP X pp) 100% of the offspring were of the dominant trait (Pp).
He let the F1 generation self-fertilise naturally which he the collected the seed of producing the F 2 generation.
(Pp X Pp) produces offspring with a 3:1 ratio.
Each time he produced a generation he recorded and examined their traits. (F 1,F2,F3, and F4)
MONOHYBRID INHERITANCE: Is the inheritance of a characteristic controlled by a single gene.
EXAMPLE: Mendel’s Pea plants.
POSSIBILITIES
If the parents were heterozygous: 3:1 purple: yellow
If the parents were PP and pp: 100% purple
If the parents were Pp and pp: 2:2 , 1:1 , 50%
If the parents were Pp and PP: 100% purple
T = tall
t = short
F1 GENERATION
PARENTS PHENOTYPE TALL SHORT
PARENTAL GENOTYPE TT Tt
GAMETES TT tt
CROSS T T
t Tt Tt
t Tt Tt
OFFSPRING GENOTYPES All Tt
OFFSPRING PHENOTYPES All tall – 100% Tall
F2 GENERATION
PARENTS PHENOTYPE TALL TALL
PARENTAL GENOTYPE Tt Tt
GAMETES Tt Tt
