notes exam I

notes exam I - animal development: notes for exam i Study...

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animal development: notes for exam i Study embryos a. Observation b. Medel organisms/technical tools Epigenesis - (Aristotle) – complexity arises through interaction of simpler parts (i.e. gametes) Preformation – all info stored in sperm; egg is ‘storage unit’ Big ideas a. Differentiation (why?) – how parts become different b. Morphogenesis (how?) – how form arises (in embryo) and mechs for such 1. Dynamic movements of tissues/cells c. Microsurgery – what cells do in new situations 1. Experiment= “the organizer” (Spemann/mangold) Dorsal lip of the blastopore Generated fate maps Permanent difs don’t begin until after division Half with blastopore develops marks differentiation ‘belly piece’ if blastopore not included Induction - organizes tissues around it Sufficiency – when a group of cells/molecs, when added to a cell/embryo/tissue, confers the ability to differentiate in a particular way a. Functional redundancy - when one molec is sufficient but not necessary (i.e. back up system) Necessity – when a group of cells/molec. Is removed from a cell/embryo/tiss. And ability to differentiate is lost a. Necessity does not mean sufficiency (i.e. need more than one factor b. Acts together w/ other cells/molecs
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Specification – the extent to which a cell/tiss. Will differentiate normall when placed into a new surrounding a. How much it should differentiate 1. Autonomous specification – differentiation would occur as it would normally, doesn’t change 2. Conditional – depends on environment Localized determinants, regulative – not much autonomous specification (can be sufficient, necessary, both) Regulative development Induction – process by which one cell/tissue sends a signal to another resulting in reproducible change Pattern formation – process> differentiation reg. of embryo/structure become specified to produce diff. structures Genomic equivalence a. Central dogma = dna> rna> protein = transcription> translation b. Not all genes expressed in a given cell c. Cloning by nuclear transfer – removal of nucleus, injection of new diploid nucleus into vacated oocyte (haploid gamete cell) 1. Age of nucleus matters> younger = better Why clone? a. Therapeudic cloning – produce genetically identical stem cells for treatment b. Reproductive cloning – produce offspring 1. Problems Large offspring syndrome- resp. probs, death after birth 33-50% larger than normal Internal organ difficulties Transgenics – contain genes from 2+ spp. Genomic imprinting
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a. Chem. Changes to DNA (methylation – prevents expression) b. All same base pairs, but not histones/proteins c. Gene expr. Differs d. Cloning = bypass regeneration of DNA’s methylation pattern, many genes control growth (igfr2) e. Dna methylation changes during maturation Compaction – midway through the 8 cell stage a. Cells become more dense b. Innercells (‘embryo proper’) – (icm – production of stem cells)
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This note was uploaded on 04/07/2009 for the course ZOO 470 taught by Professor Hardin during the Spring '08 term at Wisconsin.

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notes exam I - animal development: notes for exam i Study...

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