Download Human Genetics

Human Genetics
Concepts and Applications
Tenth Edition
RICKI LEWIS
Biol 4355 - Genética
Humana
Capítulo 1 – Repaso de
Genética
UPR – Aguadilla
JA Cardé, PhD
PowerPoint Lecture Outlines
1
Overview of
Genetics
®
Prepared by Johnny El-Rady, University of South Florida
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Objetivos
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Definir Genética y Genética Humana
Repasar conceptos básicos de Genética
Conocer aplicaciones de la Genética
Repasar momentos claves en la historia de
la Genética
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Genética vs Genética Humana
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Estudio de la herencia, mecanismos hereditarios y sus
variaciones
Incluye campos que se solapan entre si:
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genética
Citogenética
genética molecular
genética bioquímica
- genética del desarrollo
- genética clínica
- genética de poblaciones
- consejería genetica
Contesta preguntas sobre:
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la naturaleza humana
enfermedades
tratamientos
comprender la genética en la vida humana.(Wikipediahttp://en.wikipedia.org/wiki/Human_genetics).
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Genética Humana
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Estudio de la herencia según se manifiesta en seres
humanos.
Es mas sobre las variaciones que sobre nuestras
enfermedades,
Es mas sobre lo común que sobre lo raro
Antes la explicación era media oscura
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sobre conjuntos raros de síntomas,
ahora es tema de conversación diaria
Sirve de base de la ciencia médica
Antes se hablaba de un gen para algo; esto o aquello
Hoy sabemos que es mucho mas epigenesis
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son varios los genes que interactúan entre si y con el ambiente para
rasgos y condiciones
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Genética: Momentos Históricos
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Garden Peas
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DNA structure
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Gregor Mendel, 1880s
Watson, Crick, Wilkins, Franklin, 1950s
Human Genome Project
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NIH, DOE, Celera Corporation, 1990s-2000s
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Genetics
Is the study of inherited
traits and their variation
Is a life science that
should not be confused
with genealogy
Figure 1.1
Is also an informational science that is
having a huge societal impact
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Genes
Contain the instructions within the cells for
protein production
Genes are composed of deoxyribonucleic
acid (DNA)
Traits are produced by an interaction
between the genes and their environment
Figure 1.1
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The Genome
Is the complete set of genetic information
for an organism
It includes all of the genes present in an
organism
- And also DNA sequences that do not
encode genes
Genomics is a field that analyzes and
compares genomes of different species
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Levels of
Genetics
Figure 1.2
Niveles:
1. Instrucciones
2. Células Tejidos y Organos: Expresión
3. Epigenesis: Genes y Ambiente 9
Deoxyribonucleic Acid (DNA)
A double-stranded polymer consisting of a chain
of nucleotides
Deoxyribonucleotide components:
- Phosphate
- Sugar: Deoxyribose
- Base: Adenine A
Guanine G
Thymine T
Cytosine C
The sequence of the bases code for the amino
acid sequence in a protein
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Box, Figure 1
Hélice
Doble hebra
Antiparalela
Complementaria
Reading1.1, Figure 1
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Ribonucleic Acid (RNA)
A single stranded polymer of ribonucleotides
Ribonucleotide components:
- Phosphate
- Sugar: Ribose
- Base: Adenine A
Guanine G
Uracil
U
Cytosine C
Exists in several types
Uses information on DNA to construct proteins
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Box, Figure 2
Reading 1.1, Figure 2
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The Human Genome
Only 1.5% of our DNA encodes protein
- About 20,325 protein-encoding genes in all
Rest of the human genome includes highly
repeated sequences with unknown functions
Genes known to cause disorders or traits are
cataloged in a database
- Online Mendelian Inheritance in Man (OMIM)
Proteomics is a field that studies the proteins
made in a cell
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Genes
Alleles are variants of genes
They form by mutation
Mutations in sperm or egg cells are passed
on to the next generation
Mutations may be positive, negative, or
neutral
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Variations
Polymorphisms are variations in the DNA
sequence that occur in at least 1% of the
population
Single nucleotide polymorphisms (SNPs)
are single base sites that differ among
individuals
- Can cause disease or act as genomic
markers
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Variations
Genome-wide association studies track
SNP patterns among individuals who
share a particular trait or disorder
Gene expression profiling measures
which genes are more or less active in
particular cell types
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Chromosomes
Composed of DNA and protein
Found in the nucleus of the cell
Human somatic cells have 46 chromosomes
- 22 pairs of autosomes
- A pair of sex chromosomes
- Females have two X chromosomes
- Males have one X and a Y
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Karyotype
A chart displaying the chromosome pairs from
largest to smallest
Figure 1.2
Figure 1.2
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Table 1.1
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Cells
A human body contains approximately 50-100
trillion cells
- All cells except RBCs contain the same genome
Differentiation causes cells to differ in appearance
and function
- Controlled by variation in gene expression
Stem cells are less specialized and can become
many different cell types
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Levels of Biological Organization
Figure 1.3
Figure 1.3
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Table 1.2
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Individual
The genotype of an individual refers to the
alleles they carry
The phenotype is the visible trait
A dominant allele is expressed if the
individual carries just one copy
A recessive allele is only expressed if the
individual carries two copies
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The Family
Individuals are genetically connected into
families
A pedigree is a diagram used to study traits
in families
- Can be used to trace multiple genes or
genes with large environmental component
- Will be discussed in detail in Chapter 4
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A Population
Is a group of interbreeding individuals
The gene pool is the sum of all alleles in a
population
Evolution is the changing allelic frequencies
in populations over time (Hardy-Weinberg)
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Evolution
Genome comparisons among species reveals
evolutionary relationships
- The more similar the sequences are, the more
recent the divergence from a common ancestor
98% of human DNA sequences are shared
with chimpanzees
Humans share genes with mice, pufferfish,
fruit flies, yeast, and even bacteria
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Figure 1.4
Figure 1.4
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Mendelian vs. Multifactorial Traits
Mendelian traits are determined by a single gene
- Their recurrence is predicted based on Mendel’s
laws
Multifactorial traits are determined by one or more
genes and the environment
- Predicting their recurrence is much more difficult
Most traits are multifactorial
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Mendelian vs. Multifactorial Traits
Figure 1.5
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Genes and Disease Risk
Genetic determinism is the idea that the
expression of an inherited trait is inevitable
This may be harmful or helpful, depending on
its application
- As part of a social policy, it is disastrous
- Knowing genetic risks can help us make
good choices
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Applications of Genetics
Genetics impacts many areas of our lives
DNA profiling (DNA fingerprinting) looks at
SNPs and short repeated DNA sequences
- It has applications in:
- Forensics
- History and ancestry
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Forensics
Identification of victims of natural disasters or
terrorist attacks (Baby 81)
Matching the DNA of suspects to samples left
at the crime scene
Helping adopted individuals locate blood
relatives
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History and Ancestry
DNA analysis can flesh out historical details
- Revealing the offspring of Thomas Jefferson
and Sally Hemmings
- Revealing the origins of the Jewish Lemba
of South Africa
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History and Ancestry
Figure 1.6
Figure 1.7
Figure 1.7
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Health Care
Pharmacogenomics is a field that identifies
individual drug reactions based on genetics
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Health Care
Analysis of single-gene illnesses reveals
many differences from other diseases
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Health Care
Diseases are increasingly being described in
terms of gene expression patterns
Tracking gene expression can reveal new
information about diseases and show how
diseases are related to each other
- This is not obvious via traditional medicine
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The Diseasome
Figure 1.7
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Genetic Testing and Treatment
Tests to identify about 1,200 single-gene
disorders have been available for years
- Direct-to-consumer (DTC) genetic testing
The Genetic Information Non-discrimination
(GINA) act was passed in the US in 2008
Genome information is useful for developing
treatment to genetic and infectious diseases
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Agriculture
Traditional agriculture is the controlled
breeding of plants and animals
Biotechnology is the use of organisms or
their parts to produce goods and services
Genetically-modified (GM) organisms have
new genes or over- or under-express their
own genes
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Figure 1.9
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Ecology
Metagenomics is a field that involves
sequencing all of the DNA in a habitat
- The Sargasso Sea
- The Human Microbiome Project
Metagenomic studies may be used to
reconstruct ecosystems
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A Global Perspective
Genetics and genomics are spawning
technologies that may vastly improve the
quality of life
Human genome information has tremendous
potential for the entire globe
- Individual nations are using approaches
that exploit their particular strengths
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A Global Perspective
Puerto Rico?
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