The document discusses human diversity and genetics. It makes several key points: 1) There is less genetic diversity among human groups than previously thought. Differences like skin color are controlled by a small number of genes with no practical differences. 2) Racial classifications are based on external adaptations to climate and there is more genetic similarity between people of different races than differences. 3) All humans originated in Africa and migrated throughout the world, resulting in current human diversity developing in the last 50,000-60,000 years.

1. 4. Emotions
Human Genome
THE HUMAN EVOLUTION

2. Human Diversity
 Research about diversity in human groups,
made the last years, show that there are less
genetic differences among humans that it was
thought before
 The color of skin, one of the most apparent
differences, is controlled by a short number of
genes that have no practical differences
between the extremer cases
 The total amount of melanin in humans is
neither so different as it was waited before: in
people with a clear skin melanin is disposed in
deeper layers of the dermis

3.  The wrongly called “races” are a set of adaptations
acquired by the influence of climate and
expressed in different external features of the body
 That is why racial differences are basically external,
but in a genetic level all human beings have very
little differences and there may be more genetic
differences between two Europeans than between
Europeans and Africans, despite what the external
appearance may suggest
 Throughout history human species has been
precisely characterized by the tendency to crossbreeding among humans from different origins, that
is why the concept “race” has been questioned by
most of the scientific community

4.  Homo sapiens has one only origin and all human beings
living now on earth come from the same ancestral trunk
originated in Africa
 There are more genetic similarities than differences
among humans. Current human diversity has originated
during the last 50 000 or 60 000 years
 Populations emerged from Africa colonized south-east
Asia and arrived in Australia and New Guinea some
60 000 years ago and in Europe some 40 000 years ago.
The latest population belongs to north-east Asia and
America, 35 000 years ago. Native settlers in South
America come from Asia, as the similarities between
these two human groups show
 We are a “young” species, with a few genetic diversity
(differences between two individuals < 1 %). Some
10 000 years ago sedentism started

5. MIGRATIONS OF HOMO SAPIENS SAPIENS

6. Features that make us different
1. Biological features shown at the picture are
external and basically depend on
evolutionary processes regarding climate.
Then it is reasonable to expect external
appearance differences between an
African and a European
2. Instead of it, features that aren’t expressed
externally, show less differences among
human groups, due to our common origin
and the great cross-breeding happened
throughout history of mankind

7. Emotions make us human
 What are emotions?
 In 1884, psychologist Williams James proposed
himself this very question in a celebrated assay
where he introduced the definition:
“emotions are the result of perceiving
changes in our body”
Identify and enumerate the emotions
felt by the protagonist of the following
story:

8. It’s 7 o’clock p.m. and you’re walking on the street while
you’re writing absent-minded an SMS to a friend. You
suddenly realize that you’re jumping backwards in the
middle of the street while you hear the intense noise of a car
horn and creaking brakes, then you see your mobile phone
flying though the air and feel a tremendous fear. You stay sit
down on the sidewalk step and feel so happy when you
quickly guess that it’s been for short that you were not
deeply hurt and the car that was running through the street
has taken only some centimeters to knock you down. You’ve
been so lucky! But happiness only takes a moment because
you realize immediately that you’ve fallen on a dog’s shit
and you get up with disgust. But that feeling doesn’t take
too long because you can’t prevent an anger attack
against yourself because of being so careless while walking
on the street, so dangerous as it is. Your anger ends
immediately as you see that, surprisingly, your mobile has
been crashed by the car’s wheels, what arouses a feeling of
sadness in you because it was just brand-new and it had
taken you a long time to save the money to buy it

9.  When we study emotions, a basic aspect is the
controversy of including or not some related
states. We refer to what is commonly known as
feelings, including states like love, guilt or shame.
Most people do not include feelings in the
emotions catalogue because they consider they
don’t fit to the features of an emotion like these:
1. They are mechanisms devoted to give urgent
answers in our organism (prevent a danger, share
our happiness, reject a wrong food). Actually, the
word emotion comes from Latin movere, meaning
“to move”
2. They are transitory mechanisms that contribute a
value/interpretation to the experienced situation,
in such a way to condition further individual’s
attitudes (if some food has disagreed with us, we’ll
prevent having it in the future)

10. What for and why we have emotions
 As it always happens, according to the
prevailing paradigm, we must search in our
evolutionary past to find a reason that explains
why do we feel sadness, happiness or disgust.
Thanks to Darwin, who proposed the Theory of
Evolution, we know that emotions, like almost
everything produced by our brain, appeared
and were inherited from one species to
another because they made it possible to
survive and reproduce those individuals that
experimented them

11. Which functions did emotions fulfil?
 Surviving in a world full of dangers requires that and an
individual has mechanisms to answer quickly in order to
change his behavior in the best efficient way as
possible
Why did they have an adaptive value?
 Fear should have the biological function of protecting
us from danger, anger that of eliminating a competitor,
happiness that of doing again what is being lived and is
good, disgust to prevent damage, surprise to direct
attention and sadness to make us value a lost

12. How do we acquire emotions each of us ?
 During many years it’s been a matter to discuss whether
emotions were innate or not, say, if we are born with them,
or we acquire them during childhood. As far as we know
until now, our brain seems to develop with a predisposition
to experience some basic emotions: fear, anger, surprise,
disgust, sadness and happiness. These emotions have been
identified in almost every animal, they have been
described in every human culture, they appear very early in
babies’ development and each one is related to a
particular physiological answer
 It seems that these emotions automatically shoot in front of
certain stimulus, like an intense noise, but the baby or child
doesn’t learn this answer. Therefore, most of the situations
whether we shall feel one emotion or another it will depend
a lot on what the baby observes around it and the
consequences of many of its personal experiences. We
aren’t born with the innate predisposition to be happy
when we pass a school test!

13. Several techniques to get a graphic
representation of the brain
 Magnetoencephalography (MEG)
 X-ray computed tomography (CT scan)
 Magnetic resonance imaging (MRI)
 Positron emission tomography (PET)
 Regional cerebral blood flow imaging with
radioactive xenon (rCBF)
Some of these procedures allow us to find at
which cerebral zones does blood flow while we
do certain mental operations, what gives us a
clue to track them down

14. CT
scan
MEG
PET
MRI

15. rCBF

16. Cerebral circuits devoted to emotions
 The new techniques used in neurology
identify zones that are active in a given
moment. As we do not use radiations and
no substance must be injected, it is an
innocuous and very precise advance to
study the brain live. These advances have
allowed us to track down which zones are
activated when we feel these emotions. WE
CAN CHECK IT ON THE NEXT TABLE...

17. EMOTION
CEREBRAL ZONE
STRUCTURE
Fear
Amygdala
Disgust
Insula or insular
crust
Rounded shaped structure
placed at the inside part of
temporal lobe
At the bottom of Silvio's
caesura at the cortex
Anger
Orbito-frontal
crust (OFC)
Located at the cortex zone,
just above the eyes
Satisfaction
Basal ganglia
Nuclei of gray substance
located deep inside the brain
Sadness
Cingulated crust
Lower part of hemispheres

18. Zones of Human Brain

20. The Amazing Story of Phineas Gage
Phineas P. Gage was born in1832. He worked as a foreman
of a work gang blasting rock preparing the roadbed for a
railroad and was a most appreciated and respected man
by his relatives and friends. His heads were very proud of
him, for he was an involved and responsible worker. On
September 13, 1848, while he was using an iron rod in order
to introduce dynamite into a hole, the powder exploded
and the iron rod was projected and entered on the side of
his face going out at the top of his head. Surprisingly,
Phineas did not die, he did not even lose his conscience,
even though most of his left frontal lobe was completely
smashed…
…Some months after the accident, he went back to work
but a few days later he was fired. His heads said he had
become an irreverent and bad-mannered person. He
didn’t show any sort of respect for people. He was now an
uninhibited, capricious, impatient and childish person, with
no capacity of planning or foreseeing the future...

22. ...His relatives and friends also
realized the impressive change,
and they even dared say that this
person was not really Phineas.
After the lesion in his frontal lobe,
Phineas was no more the same
person. The person in which he
was transformed died on May 21,
1860. Seven years later, his body
was exhumed and nowadays his
skull and the iron rod that pierced
it lay at the Warren Museum of
the Medical College of Harvard
University
Diagram of the Phineas Gage’s cerebral lesion

23. Emotion and cognition
 Although we have tried to relate each of
the basic emotions to a specific cerebral
structure, some of these regions are
occupied in emotional processing and other
are specialized in the cognitive processing,
for example some specific zones at the
frontal crust. Cognitive aspects allow us to
modulate the intensity and expression of
emotions. Our knowledge about the world
gives us information regarding to whether it
is appropriate or not laughing, or crying, etc.
in certain situations

24.  Information exchange between emotional and
cognitive aspects can go in both ways. What means
that emotions also modulate our cognitive faculties.
For instance, that day being nervous in front of an
examination paper that you became disappointed,
although you had studied and knew your lessons
perfectly. In that case, emotions had a negative
influence and blockaded the regions devoted to
cognition
 Thanks to this interconnection between cognitive and
emotional processes, we can apply psychological
therapies, like the cognitive-conductive therapy, that
can be beneficial to correct wrong attributions, like,
for example, the depressive disorder. Some
depressions are due to a bad functioning of the
cingulated crust and those therapies help people to
make an adequate analysis about the reason of their
sadness and provide them strategies to overcome it

25. Human Genome
 1988 : Several scientific teams all over the world
start working in a coordinate way at the Human
Genome Project
 The aim was the knowledge of DNA sequences of
all human chromosomes
 Previously, scientists thought that human cells had
some 100 000 genes. Human genome sequencing,
published in 2001, has revealed that the 24
different human chromosomes (22 pairs, plus XX
and XY) had only some 30 000 genes. Now they
think there are between 20 000 and 25 000

27.  As it seems there are huge regions with apparently
no sense genetic information. Almost 95 % of
human DNA is repetitive and near 35 % of the rest
carries no information useful to synthesize any
protein. It is named as junk-DNA, with huge
“deserted” regions, without any genes, but having
a very important regulating function
 Some genes are fragmented and are hard to
identify, besides there are evidences that 35 % of
genes can be translated into proteins in cells in
different ways
http://www.genome.gov/Students/

28. Molecular models for the DNA double helix : Calotte and ball-and-stick

29. THE GENETIC CODE
There are four nitrogenous bases: ADENINE,THYMINE GUANINE and
CYTOSINE, that pair like this: A-T, G-C. The sequence of these bases
at the DNA chain is read and translated into amino acids according
to the upper table. Each triplet (codon) “means” an amino acid. U
represents the base URACIL that substitutes thymine in mRNA. A gene
is a base sequence with a meaning that can be translated

30. DNA in action: information
contained in it is translated
into mRNA (transcription) and
moves out from the cellular
nucleus to reach the
ribosomes (translation) where
protein chains are obtained
with the help of tRNA
TRADICIONAL DOGMA
OF BIOCHEMISTRY:
ONE GENE  ONE PROTEIN
Now it is thought to be more
complex

31. Advantages and risks
of knowing the human genome
 Knowledge and localization of human genes is very
important to biomedical sciences and has
unpredictable consequences
 This fact opens immense possibilities: to learn more
about human evolution, to develop therapeutic
strategies to fight and foresee genetic and hereditary
illnesses (new medicines, genetic therapy)
 But identifying the genome may also imply some
dangers, like the anticipated identification of some
illnesses and biological features that have not yet
become apparent in individuals

32.  There are genetic techniques that allow us to
identify hereditary alterations, but we may fear
that some detection tests could be used with the
aim of discriminating some people (f.e., access
to certain jobs, contracting health or life
insurances, etc.)
 We can also be concerned about human
genome manipulation with non therapeutic
purposes
 Nevertheless, advantages that can be obtained
from the application of this knowledge in fields
like health, feeding and farming do amply better
than the risks it implies
 It is possibly one of the outmost scientific projects
in history. To make an appropriate use and how
do we apply it, is a responsibility to everybody

33. Our closest “relatives”
1. Hominids and chimpanzees’ lineages split in
Africa some 6 million years ago; that’s why
we have common ancestors with
chimpanzees, but we are not descended
from them
2. From a quantitative point of view
(percentage of genetic differences), there
are more differences between a man and a
woman because we differ in a whole sexual
chromosome: women have two X
chromosomes while men have one X and
one Y

34. 3. The expression “to be more evolved” makes
no sense at all, from a biological point of
view. Evolution has followed different
pathways depending on organisms and the
environment where they were living. In some
living things some features have had an
extraordinary development while in others
not. Dogs have a better sense of smell than
us, giraffes have a longer neck and bats
have an extraordinary hearing: which one is
the “most evolved”?

35. To learn more
 ARSUAGA, J.L., MARTÍNEZ, I. La especie
elegida. Madrid: Ediciones Temas de Hoy,
2006.
 CARBONELL, E. i BELLMUNT, C. Els somnis de
l’evolució. Barcelona: La Magrana, 2003.
 AUEL, J.M. El clan de l’ós de les cavernes.
Barcelona: Columna, 1980.
 GOULD, Stephen J. La vida maravillosa.
Barcelona: Crítica, 2006.
 http://www.atapuerca.org/
 http://www.genome.gov/
 http://www.ornl.gov/