INHERITANCE AND HUMAN VARIATIONPeople are different from each other because:Genetic differences: each people (except identical twins) has their own exclusive genotypeEnvironmental factors: such as food or lifestyle. They are not transmitted in the phenotype.

TYPES OF TRAITS

Quantitive traits

Qualitive traits

HairEye colourSkin colour

Determined by a pair of allelesThere are dominant or recessive traits

The blood groups The Rh system

GENETIC STUDIES IN HUMANS

HUMAN KARYOTYPE ESTUDIESThey let us to make a comparison between the chromosomes of individuals and the species standard chromosome pattern.It helps to detect chromosome anomalies.

DIAGNOSIS OF GENETIC DISEASESSymptons of genetic disease can be treated.Some genetic diseases can be prevented if they are detected early enough.It is important to detect them before birth using the amniocentesis.

CONGENITAL MALFORMATIONSThey are the alterations in the shape, structure or sixe occurred during foetal development.It can be caused by: genetic alterations, envirnmental factors (radiation...) or infectious diseases.Examples: lims, the cleft palate, alterations in heart or liver, cataracts, deafness.Some of them can be detected using ultrasound testing.

HUMAN GENETIC DISORDERSAUTOSOMAL DISORDERS

PATTERN: ONE OF THE PARENTS HAS TO HAVE THE DISORDER

DISORDERS

DwarfismPolydactylism

Hypertension

THE PARENTS DON’T NEED TO SUFFER

DOMINANT

RECCESIVE

Albinism

SEX LINKED DISORDERS

LINKED TO X CHROMOSOME

LINKED TO Y CHROMOSOME

Hypertrichosis Ichtyosis

Colour blindness(daltonism)

Haemophilia

DISORDERS RELATED TO CHROMOSOME NUMBER

AUTOSOMAL DISORDERS

Down syndrome

SEX CHROMOSOME DISORDERS

DISORDERS THAT AFFECT WOMEN

DISORDERS THAT AFFECT MEN

Triple X syndrome• Mild learning disabilities• Delayed development of speech and motor skills Turner syndrome• Sterility• Short height

XYY syndrome• Skeleton malformations• Mild to moderate learning disabilities and aggressiveness Klinefelter syndrome• Small genitals and sterility in some cases• Mild learning disabilities

CHANGES IN CHROMOSOME STRUCTURE

DELETION:When a piece of chromosome is missing. It causes animalies in the skeleton and intellectual disabilities.Example: Cri-du-chat syndrome

DUPLICATION:When a part of chromosome is repeated.

INVERSION:When a piece of chromosome is reversed.

TRANSLOCATION:When a piece of chromosome becomes attached to a different chromosome.Example: Chronic Myelogenous Leukaemia (CML).