Welcome to Human Heredity!
DefinitionsHeredity transmission of genetic factors from
parents or ancestors to offspring or next generation
Genetics- the field of biology that studies heredity
The Cell Theory:
A cell is the basic unit of biological structure and function
All cells arise from preexisting cells
Two Types of cells on earth differ in size and complexity
– Eukaryotic (True…) cells:
– Prokaryotic (Before…) cells:
Nucleus(contains DNA)
Eukar yotic cell
Prokar yotic cell
DNA(no nucleus)
Organelles
25,0
00 ×
100 X
nucleuscytoplasm
Sperm cell
NucleicontainingDNA
Egg cell
Fertilized eggwith DNA fromboth parents
(Zygote)
Embyro’s cells with copies of inherited DNA
Offspring with traitsinherited fromboth parents
Human DevelopmentFrom single cells into a large multi-cellular organism
Unspecialized cells
Different specialized
cells
Cells• All cells of the body contain the same genetic material
made of DNA
• Differentiation causes cells to differ in appearance and function due to variation in gene expression
• Stem cells are not specialized and can become many different cell types
Electronic information
Player
Music is produced
Analogy: DNA is the genetic material of all living cells
Genetic information
Cell machinery; Gene expression
Protein is producedVisible feature or trait: color of a
flower
Genetic Material• DNA is organized inside the nucleus• Genes are the units of heredity made of segments of DNA• Linear chromosomes each with many genes• Genome all the DNA present in one cell
Two types of nucleic acids necessary for directing the activities of the cell
• DNA– One structure or shape …… one function
• RNA– Several shapes…… multiple functions
Deoxyribonucleic Acid (DNA)
• A double-stranded chain of units (deoxyribonucleotides)
• A polymer (made by connecting many)
• Each deoxyribonucleotide- Phosphate- Sugar: Deoxyribose- Bases: Adenine A
Guanine GThymine TCytosine C
Reading 1.1, Figure 2
Gene expression starts with the genetic material, DNA
1. Replicates before cells can divide
2. Directs the synthesis of proteins
The sequence of the bases code for the sequence of the building blocks, amino acids, of a protein
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
• Passes on the information and participates in directing the cells synthesis of proteins
Genetic variations• Form by mutation, changes at the DNA level
• Mutations in sperm or egg cells are passed on to the next generation
• Mutations may be positive, negative, or neutral
• Alleles are variants of genes
- Ascending vs. Descending fashion
- Each level builds on the level below it, leading to new emergent properties
- Biological systems are much more than the sum of their parts (emergence)
Levels of biological organization
Atoms/Elements
Molecules
Organelle
Cell
Tissue
Organ
Organ system
Organism(Family)
Population
Community
Ecosystem
Biosphere
Chemical world
Biological World
Non-living
Living
Ascending
Descending
– Organism: a living individual
– Family: genetically connected Individuals
– Population: a localized group of individual organisms of a species. All alleles in a population is a “gene pool”
– Community: living organisms from different populations living together in one place
– Ecosystem: all living as well as the nonliving environmental components of a place
The human body contains- About 50-100 trillion cells- 4 types of tissues- More than 260 types of cells
Levels of biologic organization
Tissues are groups of many similar cells that perform the same specific function
Tissue types• Epithelial tissue• Connective• Muscle• Nervous
https://www.youtube.com/watch?v=tKWTJ3_-1E8(~6 minutes)
Evolutionary Adaptation of populations
– Genetic diversity along with external factors including natural selection lead to differential reproductive success.
– Populations change over long periods of time– Natural selection- Charles Darwin How evolution really workshttp://www.pbs.org/wgbh/evolution/library/11/2/e_s_4.html orhttp://www.pbslearningmedia.org/resource/tdc02.sci.life.evo.howreally/evolvi
ng-ideas-how-does-evolution-really-work/
1. A basic set of genes is shared by all living organisms
2. Mutations change DNA sequence
3. Mutations take place over time
4. Sequencing of genomes shows their evolutionary relatedness.
5. Closely related organisms have more similar genes.
Genome comparisons among species - 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 have genes that are also found in mice, pufferfish, fruit flies, yeast, and even bacteria
Establishing Evolutionary Relationships
Heredity transmission of genetic factors from parents or ancestors to offspring or next generation
Genetics- the field of biology that studies heredity
Definitions
Themes of Genetics (Learning Objectives)
1. The branches of biology concerned with heredity and variation
– Genetic fields of study: Classical (Mendelian patterns of inheritance) Molecular (from DNA to protein and its control)Effect on all levels of biological organization
– Genetic variability and factors affecting variability of gene expression– DNA technologies– Genomics: analysis of genomes and their variation– Genomic technologies
2. Impact of modern genomic and DNA technologies
Change of genetics from an academic science to a clinical science with practical and societal implications for
– Health, Research, Environment– Bioethics is a field of study concerned with issues of privacy, confidentiality, and
discrimination.
Genetic Variability• Single Gene determine Mendelian Traits
– Genotype (genetic composition) leads to a phenotype (trait)
• Multifactorial traits– Influenced by:
• Other genes• Environmental factors: life style, exercise, diet
– Risk prediction: severity of symptoms (variable)– Arise from differences in protein structure, level, place, or
time of expression
Applications of Genetics and its Modern Technologies
• Identity studies (Forensics & Ancestry)• Screening for carriers of single-gene disease• Health Care (Pharmacogenomics)• Redefining Disease (Reflection of gene expression)• Genetic Testing (GINA Act value and limitations)• Agriculture (GM food and transgenic organisms)• Ecology (Metagenomics and the Microbiome project)