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Unit 4 GeneticsUnit 4 Genetics
Ch. 14 The Human GenomeCh. 14 The Human Genome
Human ChromosomesHuman Chromosomes
To analyze chromosomes, biologists photograph cells in mitosis
They then cut out the chromosomes from the photograph, & group them together in pairs
To analyze chromosomes, biologists photograph cells in mitosis
They then cut out the chromosomes from the photograph, & group them together in pairs
Human ChromosomesHuman Chromosomes
Karyotype - a picture of chromosomes arranged in pairs
Karyotype - a picture of chromosomes arranged in pairs
Human ChromosomesHuman Chromosomes
Sex chromosomes - 2 of the 46 chromosomes, that determine an individual’s sex– Females: XX– Males: XY
Autosomes - remaining 44 chromosomes
Sex chromosomes - 2 of the 46 chromosomes, that determine an individual’s sex– Females: XX– Males: XY
Autosomes - remaining 44 chromosomes
Human TraitsHuman Traits
Pedigree - chart that shows the relationships within a family
Pedigree - chart that shows the relationships within a family
Human TraitsHuman Traits
Remember that the phenotype of an organism is determined by its genotype
Also, that environmental effects on gene expression are not inherited, genes are
Remember that the phenotype of an organism is determined by its genotype
Also, that environmental effects on gene expression are not inherited, genes are
Human GenesHuman Genes
The human genome, our complete set of genetic information, includes 10’s of 1000’s of genes
The DNA sequences on these genes carry information for specifying many characteristics
The human genome, our complete set of genetic information, includes 10’s of 1000’s of genes
The DNA sequences on these genes carry information for specifying many characteristics
Human GenesHuman Genes
Many genetic disorders are caused by autosomal recessive alleles
Many genetic disorders are caused by autosomal recessive alleles
Human GenesHuman Genes
However, some genetic disorders may be caused by a dominant allele
Ex.) Dwarfism, Huntington’s Disease (loss of muscle control, & mental function until death occurs)
However, some genetic disorders may be caused by a dominant allele
Ex.) Dwarfism, Huntington’s Disease (loss of muscle control, & mental function until death occurs)
From Gene to MoleculeFrom Gene to Molecule
In cystic fibrosis, & sickle cell disease, a small change in the DNA of a single gene affects the structure of a protein, causing a serious genetic disorder
In cystic fibrosis, & sickle cell disease, a small change in the DNA of a single gene affects the structure of a protein, causing a serious genetic disorder
From Gene to MoleculeFrom Gene to Molecule
Cystic fibrosis is caused by the deletion of 3 bases in the DNA of a single gene– As a result, the body does not produce a protein
needed to transport chloride ions– CF causes serious digestive & respiratory
problems
Cystic fibrosis is caused by the deletion of 3 bases in the DNA of a single gene– As a result, the body does not produce a protein
needed to transport chloride ions– CF causes serious digestive & respiratory
problems
Cystic FibrosisCystic Fibrosis
From Gene to MoleculeFrom Gene to Molecule
Sickle cell disease is common in African Americans– It is characterized by the bent & twisted shape
of the red blood cells– The cells get stuck in the capillaries, damaging
cells, tissues, & organs– It causes physical weakness, & damage
to the brain, heart, & spleen (may be fatal)
Sickle cell disease is common in African Americans– It is characterized by the bent & twisted shape
of the red blood cells– The cells get stuck in the capillaries, damaging
cells, tissues, & organs– It causes physical weakness, & damage
to the brain, heart, & spleen (may be fatal)
Human Genes & ChromosomesHuman Genes & Chromosomes
Genes located close together on the same chromosome are linked, so they tend to be inherited together
Linked genes may be separated, however, during crossing-over
Genes located close together on the same chromosome are linked, so they tend to be inherited together
Linked genes may be separated, however, during crossing-over
Sex-Linked GenesSex-Linked Genes
Sex-linked genes - genes located on the sex chromosomes
Males have 1 X chromosome, therefore, all X-linked alleles are expressed in males, even if they
are recessive
Sex-linked genes - genes located on the sex chromosomes
Males have 1 X chromosome, therefore, all X-linked alleles are expressed in males, even if they
are recessive
Sex-Linked GenesSex-Linked Genes
Ex. of sex-linked disorders: colorblindness, hemophilia, muscular dystrophy
Ex. of sex-linked disorders: colorblindness, hemophilia, muscular dystrophy
Chromosomal DisordersChromosomal Disorders
Nondisjunction - when homologous chromosomes fail to separate during meiosis
If it occurs, abnormal #’s of chromosomes could find their way into gametes, & a disorder of chromosome #’s may result
Nondisjunction - when homologous chromosomes fail to separate during meiosis
If it occurs, abnormal #’s of chromosomes could find their way into gametes, & a disorder of chromosome #’s may result
Chromosomal DisordersChromosomal Disorders
Down Syndrome results when there is an error on chromosome 21
Down Syndrome results when there is an error on chromosome 21
Human DNA AnalysisHuman DNA Analysis
DNA Fingerprinting - (Gel Electrophoresis), analyzes sections of DNA that vary from one individual to another
DNA Fingerprinting - (Gel Electrophoresis), analyzes sections of DNA that vary from one individual to another
DNA FingerprintingDNA Fingerprinting
The Human Genome ProjectThe Human Genome Project
Genome- the entire genetic makeup of an organism
The Human Genome Project is an ongoing effort to analyze the human DNA sequence
Biotechnology companies are rushing to find genetic info. that may be used
in developing new drugs &
treatments for diseases
Genome- the entire genetic makeup of an organism
The Human Genome Project is an ongoing effort to analyze the human DNA sequence
Biotechnology companies are rushing to find genetic info. that may be used
in developing new drugs &
treatments for diseases
Gene TherapyGene Therapy
In gene therapy, an absent or faulty gene is replaced by a normal, working gene
Viruses are often used because they can enter cells so easily
In gene therapy, an absent or faulty gene is replaced by a normal, working gene
Viruses are often used because they can enter cells so easily
Ethical Issues in Human Genetics
Ethical Issues in Human Genetics
The goal of biology is to gain a better understanding of the nature of life
As our knowledge increases, so does our ability to change the genetics of living things, including humans
What will happen to the human species if we design our bodies?
The goal of biology is to gain a better understanding of the nature of life
As our knowledge increases, so does our ability to change the genetics of living things, including humans
What will happen to the human species if we design our bodies?
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