Presentation on theme: "Inheritance & Human Genetic Patterns"— Presentation transcript:
1 Inheritance & Human Genetic Patterns Chapter 12-13
2 WHY?? Thomas Hunt Morgan Early 1900’s Used fruit flies, Drosophila melanogaster to identify genetic patterns.Observed that only male fruit flies had white eyesWHY??
3 Linkage groups A group of genes located on one chromosome. These genes are usually inherited together.Example:Fruit flies have 4 pairs of chromosomes & four linkage groups.How many linkage groups do humans have?
4 Sex Determination Sex Chromosomes Autosomes X & Y Located in 23rd position (human)XX – femaleXY - maleAutosomesAll other chromosomes
5 Sex LinkageTraits that are linked to sex chromosomes.
6 Gene MapsShow the relative locations of each known gene on an organisms’ chromosome.
7 Mutations Change in DNA Germ cell mutation Somatic cell mutation Occurs in gametesDo no affect the organismMay be passed on offspringSomatic cell mutationOccurs in body cellsNot passed to offspringLETHAL MUTATIONS: cause death usually before birth
8 Gene mutationsInvolve a single nitrogen base or larger segment of DNA.Point MutationsSubstitution, addition, or removal of a single nitrogen baseMutagenEnvironmental factor that damages DNAEx. Carcinogens, tobacco, tars, UV radiation
9 Chromosome Mutations Deletion Inversion Loss of a piece of chromosome Chromosome section breaks off & reattaches in reverse orientation.
10 Chromosome Mutations cont… TranslocationChromosome section breaks off & reattaches to another, non-homologous chromosomeNondisjunctionFailure of a chromosome to separate during meiosis.
11 Results of Nondisjunction MonosomyZygote with 45 chromosomesTurners Syndrome (XO)TrisomyZygote with 47 chromosomesDown Syndrome (Trisomy 21)Klinefelters Syndrome (XXY)
15 Detecting Human Genetic Disorders Genetic ScreeningExamination of person’s genetic makeupGenetic CounselingAmniocentesisRemoval of amniotic fluid from motherChorionic Villi SamplingVilli contain same genetic makeup of fetus
16 Continued… Karyotype Ultrasound Pedigree Picture of an organisms’ chromosomesUltrasoundBouncing sound waves off fetus to create an imagePedigreeFamily record that shows how traits are inherited over several generations
18 DNA Technology Genetic Engineering Uses of DNA Technology Used to identify genes for specific traitsTransfer genes for a specific trait from one organism to another organism.Uses of DNA TechnologyCure diseasesTreat genetic disordersImprove good crops
19 Transplanting Genes Isolate a gene (ex. Insulin) Produce recombinant DNAA combination of DNA from 2 or more sources.Clone DNAAllow bacteria time to reproduceTransgenic animal: A host organism receiving recombinant DNA
20 The Human Genome Project Goals:To determine the nucleotide sequence of the entire human genome (approx. 3 billion nucleotide pairs or 100,000 genes)To map the location of every gene.
21 Gene TherapyTreating a disorder by introducing a gene into a cell or by correcting a gene defect in a cell’s genome.