Chromosomes

In our bodies, we have 23

pairs of chromosomes for

a total of 46.

Note, pair #23, consists of

the sex chromosome

pair. The first 22 pairs are

known as autosomes

Each chromosome pair consists of

two chromosomes

One comes

from one

parent

The other

comes from the

other parent

Chromosomes

Chromosomes simply

represent a condensed

form of an organism’s

DNA.

Proteins called histones

condense the DNA into a

size that can fit within the

cell nucleus

Chromosome Structure

Sex Chromosomes

XX chromosome - female XY chromosome - male

In Humans the “Sex

Chromosomes” are

the 23rd set

Karotypes

Karotypes are used to view the chromosomes of an organism.

All organisms have a specific number of chromosomes, although this

number is not unique for each organism (for example, dolphins and

rabbits have the same number of chromosomes). For example:

Adders Tonge Fern = 1260 chromosomes

Pigeons = 80 chromosomes

Donkeys = 62 chromosomes

Dolphins = 44 chromosomes

Rabbits = 44 chromosomes

Yeast = 32 chromosomes

Koala = 16 chromosomes

Fruit Fly = 8 chromosomes

Down’s Syndrome Karotype

3 chromosomes on pair #21 results in Down’s Syndrome

Down’s Syndrome

Results in the following:

-Impairment of physical and mental

development and growth

-IQ of children with Down’s Syndrome is

~50, compared to ~100 for a normal child

-Interventions and support at an early age

can help mitigate intellectual and physical

limitations

Patau’s Syndrome Karotype

3 chromosomes on pair #13 results in Patau’s Syndrome

Patau’s Syndrome

Results in major limitations in physical

development to the nervous system,

bones, muscles, kidneys, etc.

Unusual for an individual to be born with

Patau’s syndrome

Occurs in about 1 in 21,000 births

Turner’s Syndrome Kar

A missing sex chromosome results in Turner’s syndrome

Turner’s Syndrome

Individuals with Turner’s Syndrome

develop as females due to the missing

sex chromosome

Turner’s Syndrome causes the individual

to be shorter than normal, as well as

usually being infertile

A second major concern for these

individuals is the incidence of

cardiovascular problems over time

Klienfelter’s Syndrome Karotype

An extra sex chromosome results in Kleinfelter’s

syndrome

Kleinfelter’s Syndrome

Individuals with Klienfelter’s Syndrome develop as males due to the

presence of the Y chromosome.

Results in males having high concentrations of certain female

hormones as well as underdeveloped reproductive organs

A second major concern for these individuals is the high probability of

osteoporosis and breast cancer

Edward’s Syndrome Karotype

An extra chromosome on pair #18 results in

Edward’s syndrome

Edward’s Syndrome

One year survival rate of individuals with

Edward’s Syndrome is 5-10%

Picture at the right shows the physical

characteristics of those born with

Edward’s Syndrome

These individuals also have numerous

neurological limitations, cardiovascular

problems, and malformations in major

organ systems (like the digestive and

pulmonary systems)