What GENETICS is?

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What GENETICS is?

• Some defines says that it is the study of
  heredity

• But heredity phenomena were of interest to humans
  long before biology or genetics existed as the
  disciplines that we know today

• Genetics as a set of principles and analytical
  procedures did not begin until the 1860s, when
  Augustinian monk named Mendel performed a set of
  experiments that pointed to the existence of
  biological elements that we now call

GENES
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• The word genetics comes from the word gene, and
  genes are the focus of the subject

• So we can say that genetics The study of gene
  structure and action and the patterns of
  inheritance of traits from parent to offspring.

What is a gene?
A gene is a section of the (DNA)
deoxyribonucleic acid
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Why study genetics?
There are two basic reasons

1. Genetics occupies a pivotal position in the
   entire subject of biology. Therefore, for any
   serious student of plant, animal, or microbial
   life, an understanding of genetics is essential.

1. Genetics, like no other scientific discipline, is
   central to numerous aspects of human affairs. It
   touches our humanity in many different ways.
   Indeed, genetic issues seem to surface daily in
   our lives, and no thinking person can afford to
   be ignorant of its discoveries.

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The Cell

• A general characteristic of cells is their
  microscopic size.
• While there are a few exceptionsthe marine alga
  Acetabularia can be up to 5 centimeters longa
  typical eukaryotic cell is 10 to 100 micrometers.
• Most bacterial cells are only 1 to 10 micrometers
  in diameter.
• Hooke observed a honeycomb of tiny, empty
  compartments.
• He called the compartments in the cork cellulae
  (Latin, small rooms), and the term has come
  down to us as cells.

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The cell theory includes the following three
principles

1. All organisms are composed of one or more cells,
   and the life processes of metabolism and heredity
   occur within these cells.

1. Cells are the smallest living things, the basic
   units of organization of all organisms.

1. Cells arise only by division of a previously
   existing cell.

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Before we start, did you know.

• Humans are 99.9 genetically identical only
  0.1 of our genetic make-up differs.
• Our genes are remarkably similar to those of
  other life forms.
• For example, we share 98 of our genes with
  chimpanzees, 90 with mice, 85 with zebra fish,
  21 with worms, and 7 with a simple bacterium
  such as E. coli.