Post on 11-May-2020
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)