A genome is an organism’s complete set of DNA, including all of its genes. Each genome contains all of the information needed to build and maintain that organism. In humans, a copy of the entire genome—more than 3 billion DNA base pairs—is contained in all cells that have a nucleus.

Haplogroups  clans of humanity

A gene is a short section of DNA. Each gene codes for a specific protein by specifying the order in which amino acids must be joined together.

DNA (deoxyribose nucleic acid) are large and complex molecules.

They carry the genetic code that determines the characteristics of a living thing.
Chromosomes are made from long DNA molecules and are contained in the nucleus

A genome is an organism’s complete set of DNA. Each genome contains all of the information needed to build and maintain that organism.

A copy of the entire genome   —  more than 3 billion DNA base pairs

 – is contained in all cells that have a nucleus.

Human body cells have 23 pairs of chromosomes in the nucleus.

MITOSIS Cell division producing Genetically identical cells

MEIOSIS Cell division producing Gametes ; a male gamete fuses with a female gamete to produce a new cell, contain a single set of chromosomes, whereas body cells contain two sets of chromosomes.

CHROMOSOME

What is a chromosome?
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.

Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.” The short arm of the chromosome is labeled the “p arm.” The long arm of the chromosome is labeled the “q arm.” The location of the centromere on each chromosome gives the chromosome its characteristic shape, and can be used to help describe the location of specific genes

How many chromosomes do people have?
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.

The 22 autosomes are numbered by size. The other two chromosomes, X and Y, are the sex chromosomes. This picture of the human chromosomes lined up in pairs is called a karyotype.

The 22 autosomes are numbered by size. The other two chromosomes, X and Y, are the sex chromosomes. This picture of the human chromosomes lined up in pairs is called a karyotype.