Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 11: Gene regulation: very brief overview Stem cells Differentiation Examples in plants and animals that every cell has the genetic potential to become an entire organism.

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In recent years umbilical cord and placental blood has been collected at birth BIOLOGY AND SOCIETY: BABY’S FIRST BANK ACCOUNT Figure 11.1

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Four of the many different types of human cells FROM EGG TO ORGANISM: HOW AND WHY GENES ARE REGULATED –They all share the same genome –What makes them different? Figure 11.2 (a) Three muscle cells (partial)(b) A nerve cell (partial) (c) Sperm cells(d) Blood cells

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In gene expression Patterns of Gene Expression in Differentiated Cells –A gene is turned on and transcribed into RNA –Information flows from genes to proteins, genotype to phenotype The regulation of gene expression plays a central role in development from a zygote to a multicellular organism

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Patterns of gene expression in specialized human cells Figure 11.3 Pancreas cell Eye lens cell (in embryo) Nerve cell Glycolysis enzyme genes Crystallin gene Insulin gene Hemoglobin gene Key: Active gene Inactive gene

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Warmup:When your started out, you were a single cell. Your are now made of many cells; some of these cells function as liver cells, some as muscle cells, some as red blood cells. What name is given to the process that is responsible for this? 1.regeneration 2.carcinogenesis 3.cellular differentiation 4.morphology 3% 1% 94% 2%

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A DNA microarray allows visualization of gene expression DNA Microarrays: Visualizing Gene Expression mRNA isolated cDNA made from mRNA cDNA applied to wells 4 Unbound cDNA rinsed away Reverse transcriptase and labeled DNA nucleotides DNA microarray (each well contains DNA from a particular gene) Fluorescent spot Nonfluorescent spot cDNA DNA of gene Figure 11.4a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The pattern of glowing spots on a microarray enables researchers to determine which genes are turned on or off Figure 11.4b

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Warmup:The process by which genotype becomes expressed as phenotype is ________________. 1.recombination 2.transcription 3.phenogenesis 4.gene expression 1% 14% 0% 85%

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Warmup: Which of these techniques could tell you how gene activity differs between individuals with and without cystic fibrosis? 1.amniocentesis 2.X ray crystallography 3.DNA microassay 4.Karyotyping 17% 7% 58% 18%

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Differentiated cells The Genetic Potential of Cells –All contain a complete set of DNA –May act like other cells if their pattern of gene expression is altered

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.5 Root of carrot plant Root cells in growth medium Cell division in culture Single cell Plantlet Adult plant The somatic cells of a single plant can be placed in a growing medium to produce clones Differentiated plant cells have the ability to develop into a whole new organism

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Nuclear transplantation Reproductive Cloning of Animals –Involves replacing nuclei of egg cells with nuclei from differentiated cells –Has been used to clone a variety of animals

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Scottish researchers cloned the first mammal in 1997 –Dolly, the sheep, was the product of their work

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The procedure that produced Dolly is called reproductive cloning Figure 11.6 Remove nucleus from egg cell Donor cell Add somatic cell from adult donor Nucleus from donor cell Grow in culture to produce an early embryo Reproductive cloning Implant embryo in surrogate mother Clone of donor is born Therapeutic cloning Remove embryonic stem cells from embryo and grow in culture Induce stem cells to form specialized cells for therapeutic use

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Other organisms have since been produced using this technique, some by the pharmaceutical industry Figure 11.7 (a) Piglets(b) Banteng

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Can clones occur in nature in mammals? 1.Yes 2.No

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Embryonic stem cells –Can give rise to specific types of differentiated cells

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8 Cultured embryonic stem cells Different culture conditions Liver cells Nerve cells Heart muscle cells Different types of differentiated cells

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Adult stem cells –Generate replacements for nondividing differentiated cells –Are unlike ES cells, because they are partway along the road to differentiation

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In 2001, a biotechnology company announced that it had cloned the first human embryo Figure 11.9

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Which type of cell has the most potential to differentiate into the many different cell types? 1.Embryonic stem cell 2.Adult stem cell 3.Somatic cell 4.Cloned cell

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Should we pursue cloning in all animals except humans? 1.Yes 2.No 3.Not sure

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Should we pursue human cloning for the purpose of developing or performing medical treatments? 1.Yes 2.No 3.Not sure

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Is your clicker working? 1.Yes 2.No

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Which example below provides evidence that every cell in the body has the potential to make a whole new organism? 1.DNA microarrays 2.Differential gene expression 3.Cloning 4.Adult stem cells

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings What is therapeutic cloning? 1.Adult stem cells are induced to grow different types of cells. 2.Nucleus from an adult cell is used to make an embryo. The ES cells are taken from that embryo and induced to form a specific cell type. 3.Nucleus from an embryonic stem cell is used to make an embryo. The ES cells are taken from that embryo and induced to form a specific cell type. 4.Adult stem cells are used to clone an organism. 5.Embryonic stem cells are used to clone an organism.

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings List differences between Adult stem cells and Embryonic stem cells:

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How is gene expression regulated in a cell? THE REGULATION OF GENE EXPRESSION –The metaphor of the plumbing in a house is useful Figure Unpacking of DNA Transcription of gene Processing of RNA Flow of mRNA through nuclear envelope Translation of mRNA Various changes to polypeptide Breakdown of protein Chromosome Gene DNA IntronExon RNA transcript Cap Tail mRNA in nucleus mRNA in cytoplasm Polypeptide Active protein Broken down protein Nucleus Cytoplasm Breakdown of mRNA

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings If the DNA is packed tightly will the gene be expressed? 1.Yes 2.No

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings If the RNA is degraded quickly after leaving the nucleus will the gene be expressed? 1.Yes 2.No

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Homeotic genes EVOLUTION CONNECTION: HOMEOTIC GENES –Are master control genes –Regulate many other genes –Help direct embryonic development in many organisms Figure 11.21

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Homeoboxes –Are sequences of nucleotides common in many organisms –Can turn groups of genes on and off during development

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Fly chromosome Fruit fly embryo (10 hours) Adult fruit fly Mouse chromosomes Mouse embryo (12 days) Adult mouse

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Warmup: What is the difference between embryonic and adult stem cells? 1.The use of embryonic stem cells raises fewer ethical issues than the use of adult stem cells. 2.It is easier to induce dedifferentiation in adult stem cells. 3.Embryonic stem cells are undifferentited; adult stem cells are partially differentiated. 4.Embryonic stem cells are harder to isolate than are adult stem cells. 7% 17% 66% 10%

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Warmup: The use of _________________ holds promise for the treatment of diseases such as Parkinson's disease. 1.nuclear transplantation 2.therapeutic cloning 3.reproductive cloning 4.eugenics 7% 69% 10% 14%