5. Gene expression is the process by which inheritable information from a g
is made into p or R .
Gene expression is the process by which inheritable
information from a gene is made into protein or RNA.
What the relationship among genes, phenotype and
environment?
In plain language gene expression is how a gene works. Gene
expression functions in the environment of the living organism. If
the environmental factors are not correct then the characteristic
produced by the gene may not be expressed. The way an organism
physically looks is called its phenotype. The phenotype is determined by genes
but is influenced by toe organisms’ environment.
6. An allele is an alternative form of a gene (one
member of a pair) that is located at a specific
position on a specific chromosome.
7. 7
Heredity and Variation—Heredity and Variation—
all living organismsall living organisms
hereditaryhereditary
factorfactor Theory ofTheory of GeneGene
8. Genetics is a diverse subject concerned with
variation and heredity in all living organisms.
Human genetics is the science of variation and
heredity in human beings.
10. 10
MEDICAL GENETICSMEDICAL GENETICS
Medical Genetics is the application
of genetics to medical practice.
Diseases —
Inheritance
Clinical Genetics
Diagnosis
Prevention
Counseling Treatment
11. 1865, Mendel G1865, Mendel G
Law of SegregationLaw of Segregation
Law of Independent AssortmentLaw of Independent Assortment
A Brief History of GeneticsA Brief History of Genetics
12. 12
1865, Mendel G1865, Mendel G
Experiments in Plant HybridizationExperiments in Plant Hybridization
13. 1. Law of Dominance:
- In a cross of parents that are pure for
contrasting traits, only one form of the
trait will appear in the next generation.
- Offspring that are hybrid for a trait will
have only the dominant trait in the phenotype.
2. Law of Segregations:
- During the formation of gametes (eggs or sperm), the two alleles (hereditary
units) responsible for a trait separate from each other.
- Alleles for a trait are then "recombined" at fertilization, producing the genotype
for the traits of the offspring.
3. Law of Independent Assortment:
- Alleles for different traits are distributed to sex cells (& offspring) independently
of one another.
Image: Gregor Mendel, Mendel's Principles of
Heredity: A Defense by Bateson, WilliamFrom the Virtual Cell Biology Classroom on ScienceProfOnline.com
14. 1902, Garrod AE1902, Garrod AE
Inborn errors of metabolismInborn errors of metabolism::
alkaptonuria(AR)alkaptonuria(AR)
1908, Hardy GH & Weinberg W1908, Hardy GH & Weinberg W
Law of Genetic EquilibriumLaw of Genetic Equilibrium
1909, Nilsson-Ehle H1909, Nilsson-Ehle H
Multifactorial inheritanceMultifactorial inheritance
15. 15
Law of Linkage and Crossing OverLaw of Linkage and Crossing Over
Theory of Gene (1926)Theory of Gene (1926)
1933
16. 16
1944, Avery OT, et al1944, Avery OT, et al
DNA is the genetic materialDNA is the genetic material
18. 18
DNA double helix structureDNA double helix structure
X-ray diffraction photograph of the
DNA crystal taken by scientist
Rosalind Franklin.
http://www.expeditions.udel.edu/extre
me08/genomics/history.php
http://en.wikipedia.org/wiki/DNA
53. Use library resources to define the following words and
write their definitions using your own words.
allele:
genes:
dominant :
recessive:
homozygous:
heterozygous:
genotype:
phenotype:
Mendelian Inheritance:
53
Editor's Notes
视盘充血，盘周有毛细血管扩张及神经纤维肿胀，视网膜动静脉不同程度迂曲扩张
Optional: For this task, pre-arrange with a school librarian or media specialist to provide students with the computers with the web sites, “Talking Glossary of Genetic Terms” (http://www.genome.gov/10002096) and/or “DNA from the Beginning’s Classical Genetics” (http://www.dnaftb.org/dnaftb/), in addition to other reference materials student pairs can used to complete the task.
Hand out the Basic Genetic Terms worksheet and provide reference materials for students to use in completing the worksheet.
Have student pairs take turns in sharing their definitions and examples of the terms. (See the Basic Genetic Terms for Teachers for sample definitions and examples.)
