Genetics Test 1 Study Guide CH 1 Iceland Parliament passed deCODE Genetics Database drawn from medical records and could cross reference medical information with genealogical database and correlate information with results from DNA samples of donors Scientists can search for genes with complex disorders Iceland was good for this because the people in Iceland have a high level of genetic relatedness due to the founding of Iceland by a small population drawn mainly from Scandinavian and Celtic Sources Early Concepts Pangenesis Specific particles gemmules carry information from body to reproductive organs which are passed to embryo at conception Inheritance of Acquired Characteristics Traits acquired in life were incorporated into hereditary information and passed on artist would pass on art skills to offspring Proposed by Greeks Golden Age of Greeks Hippocratic School of Medicine Hippocrates Active humors in parts of the body served as bearers of hereditary traits that were passed on to offspring Diseased humors accounted for deformations and disorders Male semen contained a vital heat that produced offspring of the same This heat cooked and shaped the menstrual blood and it became the physical substance that gave rise to the offspring Aristotle form as the parent William Harvey 1600s Theory of epigenesis States an organism develops from the fertilized egg by a succession of development events that eventually transforms the egg into an adult Conflicted with preformation states that the fertilized egg contains a complete miniature adult called a homunculus Robert Hooke 1665 Discovered cell using the microscope Mathias Schleiden and Theodor Schwann 1830 Cell theory All organisms are composed of basic units called cells Creation of living organisms from non living components Louis Pasteur Spontaneous Generation Charles Darwin Published Origin of Species species Existing species arose by descent with modification from ancestral Natural selection individuals with heritable traits will survive and reproduce Chromosomal Theory of Inheritance Sutton and Boveri Heredity and development were dependent on genetic information in genes contained in chromosomes Gregor Mendel Experiments with pea plants traits passed from parent to offspring in Each trait is controlled by a pair of genes and during gamete formation predictable ways members of gene pair separate Experiments with fruit flies showed mutant traits could be traced to a single chromosome confirmed that genes are carried on chromosomes Chromosomes are copied and distributed so each daughter cell receives a set Cells produced receive only one chromosome from each pair resulting in Mitosis identical to the parent Meiosis haploid number Phenotype Genotype Observable features Given trait by a set of alleles alternate form of gene Proteins and DNA major chemical components of chromosomes James Watson and Francis Crick Described the structure of DNA as a long ladder like macromolecule that twists into a double helix with each linear strand made up on nucleotides A adenine G guanine T thymine C cytosine Transcription Translation DNA constructs complementary RNA sequence RNA moves to cytoplasm where mRNA binds to a ribosome Synthesis of proteins under the direction of mRNA making the genetic code consists of linear series of nucleotide triplets codons Codons specifies insertion of a specific amino acid to a protein tRNA helps proteins assemble within ribosomes Proteins are the end products of gene expression Enzymes Form largest categories of proteins Biological catalysts Recombinant DNA Restriction enzymes are used to cut DNA at specific sequences to make fragments Can be inserted into carrier DNA with vectors forming recombinant DNA CHAPTER 2 Eukaryotic cells where rRNA is synthesized Prokaryotic Cells Nucleus house genetic material DNA and thin fibers as well as nucleolus Lack nuclear envelope and membranous organelles Genetic material is in long circular DNA molecule in nucleoid area Chromosomes Centromere condensed region that is where the arms of the chromosome Submetacentric between middle and end extend from connects two parallel sister chromatids Metacentric middle Acrocentric close to end Telocentric at the end P arm shorter arm Q arm longer arm Diploid number all somatic cells derived from members of the same species contain identical number of chromosomes Homologous Chromosomes chromosomes existing in pairs contain identical gene sites along their lengths locus Sister chromatids identical copies of a chromosomes Most viruses and bacteria only have 1 chromosome Genetic information contained in a haploid set of chromosomes Genome Biparental inheritance each diploid organism contains 2 copies of each gene During formation of gametes or spores meiosis converts diploid of chromosomes to haploid of chromosomes to haploid which results in a haploid gamete or spore containing one member of each homologous pair of chromosomes Following the fusion of 2 gametes in fertilization the diploid is reestablished zygote contains 2 complete sets of haploid chromosomes Exception sex determining chromosomes are not homologous MITOSIS daughter cells In adults mitotic activity wound healing and cell replacement Karyokinesis nuclear division when genetic material is partitioned into Cytokinesis follows karyokinesis cytoplasmic division Following division daughter cells are the size of the parent but nucleus is equal in size Cell division contains 3 checkpoints If a mutated cell allows itself to proceed through cell cycle as one of the population of regular cells this genetically altered cell would divide uncontrollably tumor cell INTERPHASE Initial stage when replication of the DNA of each chromosome occurs G1 phase before S phase when cells follow 1 of 2 pathways Either withdraw form the cycle become quiescent and enter G0 stage Cancer cells either avoid G0 or go through it very quickly to mass produce Commit to initiating DNA synthesis and enter the S phase S phase DNA is synthesized before mitosis G2 phase centrosome replicates by the end the volume of the cell has doubled DNA has been replicated and mitosis is initiated PROPHASE disappears Often of mitosis is spent in prophase Centrioles begin to migrate the nuclear envelope breaks down and Chromatin fibers begin to condense into chromosomes At or near the end of prophase you can see sister chromatids connected at the centromere by cohesion multi subunit protein Chromosome configuration to metaphase