Inheritance of organisms

Sudarshana ElapathaNational Dip. In Teaching

Derive a quality or characteristic from

one's parents is known as inheritance

The passing down characteristics genetically from one generation to another is called heredity.

Heredity .

The observable characteristics of an

individual resulting from the interaction of its

genotype with the environment.

Phenotype

The genetic constitution of an individual organism.

Genotype

Skin colour (Brown / tan ) Hair colour (Black/Brown) Colour of the Eyes (Black/Brown) Nature of hair (Curly/Strait) Nature of the ear lobes(Free or not) Right-handedness Inability to roll the tongue Nature of hands are folded, Height

Inherited characters

Syndactyly - Two adjacent fingers are bound together to some distance by a fold of skin.

Polydactyly - Possession of 6 fingers or toes.

Albinism - Possession of a very white skin, blonde hair, and white eye lashes

Brown or blue eyes -

Hereditary features that are rarely met

Characters that are dependent on Climatic differences, Environmental conditions Nutrition Exercise or activities Explore to harmful rays Diseases are not inherited characters.

They are called Non-inherited characters

Non-inherited characters

How are characters

inherited from generation to generation?

When a black child was born to

white parents what will

happen?...

A hidden character

among the parents is expressed through the

child.

generations by

chromosomes

Inherited characters are transformed

through

Chromosomes are

Genes

which are carried by

inheritance of characters

Responsible for.(

Mendel’sexperiment

Mendel used

garden pea plantsPisum sativum

for his experiment.

He carried out his experiments according to the scientific

method giving special attention to the

following points

Selecting a suitable organism

Hybridization of only one character at a time (mono hybridization)

Planning simple experiments and recording all the observations continuously and regularly

Developing hypothesis based on the observations and rechecking the hypothesis

Special characters

selectingGarden pea

Having contrasting characters

Pure line of characters

Natural reproduction

by self pollination

are protected

due to occurrence of

seeds

It was possible to produce

by cross pollination

They had

life cycle

a short

offspring

Hybridized plants

producedfertile

easily

we

re germinated

Seeds

Experiment Done by Mendel

In the ratio

Based on his observations,

Mendel disclosed

There are two factors

controlling each contrasting trait

of an organism

When gametes from these factors separateand only one factor

enters a gamete

In a monohybrid,

of the morphological ratio

betweenthe dominant and recessive

traits is

3:1 in the F2 generation

In this F2 generation

the ratio among homozygous dominant

pairs heterozygous pairs:

homozygous recessive pairs

is 1:2:1 and is also known as

the genotype ratio

In heredity the male and female organisms

selected for hybridization

is known as

the parental generation (P).

Their offspring is known as filial generation (F).

The first generation of offspring is F1

while the second

generation is F2.

Gene linkage occurswhen two or more genes are linked

on the same chromosome,

they are called linked genes.

Linked genes

on X or Y Chromosome

sare known as Sex linked genes

Haemophilia andcolour blindnessare sex linked geneson X chromosomes.

The genotype colour blindness

XcXc or XcY

The heterozygous genotype XCXc acts as carries of the disease.

The genotypeHaemophilia X

hY

The heterozygous genotype XHXh

is a carrier female

Incomplete dominance

coloured

The four ‘O’ clock flowers

( Mirabilis jalapa)

bear

flowers

flowers

Prominent homozygous

produce

flowers

Recessive homozygous

produce

Because the dominant gene (R)

is incapable of

completely overriding

the recessive gene(r).

Heterozygous genotypeRr produces magenta Coloured flowers.

This phenomena

is known as incomplete dominance