All babies are born with a kind of prearranged pattern as a result of a process of transmission of genetic characteristics from the parent to the

offspring , called HEREDITY.

BEHAVIOR GENETICS combines the methods of genetics and psychology to study the

inheritance of behavioral characteristics.

Physical characteristics:

height bone structure the color of the hair and eyes are inherited

Psychological characteristics:

ability temperament emotional stability are transmitted from parents to offspring.

The hereditary pattern is

transmitted at conception when

female egg is fertilized but the

male sperm cell. The union of the egg and the sperm within the mother’s body result in a new cell called a

zygote.

During the prenatal period, when the fetus is in the mother’s womb, the systems and structures it will need to function as a separate being develop.

The hereditary units that we receive from our

parents and transmit to our offspring are

carried by microscopic particles known as CHROMOSOMES ,

colored bodies found within the nucleus of each cell in the body.

The human cell contains 46

chromosomes arranged in 23 pairs.

Each chromosomes is composed of many individual hereditary units called

Genes, which also occur in pairs – one gene in each pair comes from the

sperm chromosomes and one gene from the ovum chromosomes. Thus, a

child receives only half of each parent’s total genes. The complete set of genes is called the human Genome. The total

number of genes in each human chromosomes is around 100,000.

One exception is identical twins, who is having developed from the same fertilized egg, have exactly the same chromosomes and genes.

The actual carrier of hereditary information within the genes is a complex nucleic acid called DNA (deoxyribonucleic acid). DNA

gives special “ hereditary instructions” for the cellular development of the organism and these instructions are partially carried

out by RNA .

The potential importance of the discovery of both DNA and RNA is that once we know how these substances give instructions and how the instructions are carried out, we may be able to correct faulty growth in mankind such as inherited abnormalities. These have been the work of scientists in what is referred to as genetic engineering

Test tube or in – vitro fertilization (IVF) , CLONING and other experiments on

the human life and nature are in active development in this age of

highly advanced technology. These developments offer many marvels as science expands its growing ability to

improve on nature.

This high tech baby making involves removing eggs from a female them outside the body with sperms from a male and then putting them back into a uterus to grow.

In the Kotulak and Gorner report (19950 , it says that in Vitro fertilization (IVF) has

made possible every permutation of egg, sperm and womb. Because of this, human

embryos may be mixed and matched, frozen and stored and may become the subjects of property disputes and make definitions of modern parenthood fuzzy.

Through IVF , parents can now determine the sex and kind of children they want.

Scientists hugged the limelight in genetic engineering in their campaign to put information about DNA to use quickly as

possible in the treatment and prevention of human diseases

On January 17, 1994, by P.E. Dewitt were the works of Dr. Francis Collins who leads a 15 year project at the U.S. National Institute of Health .

The project is called the Human Genome Project which aims to draw the details of the human

genome or the DNA . As reported DNA in their hands has become both a blueprint and a drug, a

pharmacological substance of extraordinary potency that can treat not just symptoms or

diseases that cause them but also the imperfections in DNA that make people

susceptible to a disease.

Four molecule “ Letters” called nucleotides – ADENINE (A), CYSTOSINE (C) , QUANINE (G) and THYNINE (T). By scanning a data base containing the complete sequence of letters , researchers could quickly end up at a particular gene’s front door.

This process is used to locate defective or “ broken genes.” Once a “broken” gene is found , the next thing for the gene engineers is to come up with a strategy to replace bad nucleotide one letter at a time.

Cloning is duplicating a human embryo where the cells are simply copied with their genes intact. It

seems like a simple process; in fact , agricultural, researchers have used it to clone embryos from cattle, pigs, and other animals for more than a

decade now

Dolly (5 July 1996 – 14 February 2003) was a female domestic sheep, and the first mammal to be cloned from an adult somatic cell, using the

process of nuclear transfer.  She was cloned by Ian Wilmut, Keith Campbell and colleagues at

the Roslin Institute near Edinburgh in Scotland. She was born on 5 July 1996 and she lived until the age

of six.  She has been called "the world's most famous sheep" by sources including BBC

News and Scientific American. The cell used as the donor for the cloning of Dolly was taken from a

mammary gland, and the production of a healthy clone therefore proved that a cell taken from a specific part of the body could recreate a whole

individual. On Dolly's name, Wilmut stated "Dolly is derived from a mammary gland cell and we couldn't think of a more impressive pair of glands than Dolly

Parton's".

Zone Pellucida – strip away an outer coating that is essential to development.

Related to ethical issues, Many scientists and physicians strongly believe that it would be unethical to attempt to clone

humans . With so many unknowns concerning reproductive cloning, the

attempt to clone humans at this time is considered potentially dangerous and

ethically irresponsible.

If both members of a gene pair are dominant, the individual will manifest the trait determined by

the genes. If one dominant and the other is recessive, the individual will show the form of the

trait determined by the dominant gene but will also carry the recessive gene, which may be expressed in a different way as a trait in the offspring. A recessive form of the trait will be

expressed only if the genes contributed by both parents are recessive. The genes determining eye color, for example, act in a pattern of dominance and recessiveness. Blue eyes are recessive. Thus, for a child to be blue-eyed, both parents must be blue-eyed, or if one parent is brown-eyed parents can produce a blue-eyed only if both carry a gene

for blue eyes.

For example, brown hair is a dominant trait over blonde hair. So if someone inherits a blonde hair gene from the mother and a brown hair gene from the father, they will have brown hair. The dominant allele for brown hair will override the blonde hair allele.

RecessivenessA recessive trait is which requires two copies of the gene to show up. For example, blonde hair is recessive, so it will only be present in the child if both parents donate a blonde hair allele. This is sometimes called a double recessive.

Dominant Gene Recessive Gene

Brown eyes

Dark or brunette hair

Curly hair

Normal hair

Normal color vision

Normal hearing

Normal coloring

Immunity to poison ivy

Normal blood

Blue eyes

Light, blond, and red hair

Straight hair

Baldness

Color Blindness

Congenital deafness

Night blindness

Susceptibility to poison ivy

Hemophilia – failure of blood to clot

We cannot tell what genes a person has inherited simply by looking at him. Looking

at a person tells us his phenotype or genetic inheritance as noted in his observable characteristics. The person’s genotype

includes all genetic characteristics, seen and unseen, dominant and recessive. A person

who has a dominant gene for brown skin and recessive gene for fair skin, for example, has a phenotype (appearance) of brown skin but a genotype (genetic makeup) of brown skin

with a recessive gene for fair skin.

Similarities between organisms of any one kind are determined by heredity. Individuals of the same family have similar genes and traits . The reason is that each parent contributes half

of his or her genes to his or her children. Some of the genes of a brother and sister are sometimes identical . So too , are some of the

genes of parent and child.

1. Heredity has an important influence in determining intelligence

2. Environment has substantial effects on intelligence

3. Both heredity and environment play a profound role in a person’s score on intelligence test.

Inheritance of Emotionality

Male and female chromosomes appear the same when examined under the microscope, except pair number 23, the sex chromosomes . The first 22 pairs are called Autosomes. Pair 23 determines the sex of the individual and carries genes for certain traits the are called “sex – linked”.

a man marries a woman

XHxh xHyH XH YHXH XHXH XHYHXh XhXH XhYH

Heredity and maturation do not mean the same thing. Heredity , as we have seen is the direction and pattern given by the genes to growth and development .

Maturation is the completion of growth and development within the organism, the unfolding of

an individual’s inherent traits or potentials.

Maturation is not the same as learning, since changes due to maturation are determined by heredity. For example , a newborn baby cannot learn to walk, no matter how much instruction he is given. Only when his body structure has developed sufficiently due to maturation can be taught to walk.

The development of language following shortly after birth is achieved in the kind of orderly sequence that characterizes motor development in the average child. A great deal of learning goes on before a child utters his first word.

Human learning cannot be accounted for solely in terms of maturation but learning does take place most efficiently when the environmental stimulation is keyed to the degree of maturation of the individual. A child can learn to read most efficiently if

he is given instruction in reading at a time when he has achieved a sufficient degree

of maturation.

Environment includes all the conditions inside and outside an

organism that in any way influence its behavior , growth , development or

life processes except the genes.

The external physical environment is made up of all the many things in the world that affect us directly ( as food does) and all the things that stimulate our sense organs (sight and sounds do).

The social environment includes all the human beings who in any way influence us. All these social influences occur because as human beings , we must learn to live in the world and cope with the exigencies of life. We are able to learn a great many kinds of adaptive behavior that fit us to changing environmental situations.

“Great Qualities are partly the gift of God, partly the result of good training and effort”

- Anonymous