* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics - TeacherWeb
Population genetics wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Human genome wikipedia , lookup
Gene desert wikipedia , lookup
Gene therapy wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Public health genomics wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Genetic engineering wikipedia , lookup
Ridge (biology) wikipedia , lookup
Point mutation wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Minimal genome wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Genome evolution wikipedia , lookup
Gene expression profiling wikipedia , lookup
Neocentromere wikipedia , lookup
Genomic imprinting wikipedia , lookup
Y chromosome wikipedia , lookup
History of genetic engineering wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Gene expression programming wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
X-inactivation wikipedia , lookup
Genome (book) wikipedia , lookup
Genetics: • Branch of biology dealing with genes and heredity • Genes: bits of DNA on chromosomes • Usually 2 genes for a trait Dominant Gene: always seen in the population – represented by a capital letter Recessive Gene: overpowered by the dominant gene – represented by a small letter • Trait: a feature or characteristic (eye color, hair color) • Alleles: different forms of a gene on a homologous chromosome Gregor Mendel (1822-1884) The “Father of Genetics” • Austrian monk who worked with pea plants (28,000 plants in a 10 year span) Use of favorable material (easy to raise) Self-pollination (creation of pure strains) and cross-pollination possible Discontinuous traits (2 contrasting forms) Could study 1 trait at a time Large numbers of offspring produced Mendel’s Three Laws: • Law of Dominance: One gene can mask another gene (dominant versus recessive) Phenotype: the appearance of the organism Genotype: the arrangement of genes Homozygous Dominant (FF) Homozygous Recessive (ff) Heterozygous (Hybrid) (Ff) • Law of Segregation: In gamete formation, genes are separated Rule for # of gametes: 2n (n= # of hybrids) • Law of Independent Assortment: In gamete formation, genes separate independent of each other Exception: linkage (blonde hair, blue eyes) Rules for Problem-Solving: • • • • Write down dominant and recessive genes Write down parents’ genes (P generation) Get parents’ gametes Do the cross on a punnett square (board for offspring possibilities – F1 generation) • Get results and label answer Types of Problems: • • • • • Simple 1 trait cross Monohybrid Cross (Ff X Ff) Genotype: 1:2:1 Phenotype: 3:1 Simple 2 trait cross Dihybrid Cross (FfDd X FfDd) Phenotype: 9:3:3:1 Incomplete Dominance (3 phenotypes present) Andalusian Fowl FF (black) ff (white) Ff (blue) Roan Cattle FF (brown/reddish) ff (white) Ff (brown with white) Four O’Clock Flowers FF (red) ff (white) Ff (pink) • Multiple Alleles: traits with more than one pair of alleles Examples: Rabbits (coat color) Humans (blood groups) • Human Blood Groups • • • Karl Landsteiner Also called Codominance (2 dominant alleles/1 recessive allele) A and B = dominant O = recessive 4 Human Blood Types: A B AB O (phenotypes) Type A: AA AO (genotypes) Type B: BB BO (genotypes) Type AB: AB (genotype) Type O: OO (genotype) • Test Cross: used to determine the genotype of an organism Use homozygous recessive X the unknown genotype • 1903 Walter Sutton: factors as genes • 1909 Thomas Hunt Morgan: Colombia University - used Drosophila melanogaster as a research animal Easy to raise Eat simple food Life cycle (10-15 days) many generations Easy to distinguish the sexes 4 pairs of chromosomes (3 pairs of autosomes) Large salivary gland chromosomes Easy storage 1 pair of sex chromosomes with sex-linked traits (white eyes) XX, XY • Genetic Maps: specific location of genes on chromosomes Crossing over of genes (“jumping genes”) Barbara McClintock: research with corn Mutations • A change in DNA (a “mistake” in DNA) Add diversity Most are recessive Not usually positive Inherited Caused by mutagens (chemicals, food additive, radiation, viruses) • Somatic Mutation: in body cells (not passed on) • Germ Mutation: in sex cells (passed on) • Gene Mutation: Deletion (a gene is omitted) agethol Insertion (a gene is added) agethol Frameshift (a section is reversed) agethol agetol agethoyl aolgeth • Chromosomal Mutation: Inversion: piece of a chromosome breaks off and reattaches itself to the same chromosome backwards Translocation: piece of one chromosome breaks off and reattaches itself to a different chromosome (Stillbirths) • Human chromosome number = 46 (2n) n = # of chromosomes in a sperm or egg • Aneuploidy = 1+ or - the 2n number (either 45 or 47 chromosomes) Monosomy: 45 (2n-1) Turner’s Syndrome (X_) Sterile female underdeveloped Trisomy: 47 (2n+1) Down’s Syndrome (extra #21 chromosome) Kllinefelter’s Syndrome (XXY) Sterile male feminized (XYY) Tall male with acne (criminal tendencies) (XXX) Fertile female (mentally challenged) • Polyploidy: whole sets of chromosomes are inherited (3n, 4n, etc.) plants • Human chromosome number = 46 (2n) n = # of chromosomes in a sperm or egg cell Sex Linked Condition: recessive abnormality on the X chromosome Hemophilia: XHXH XHXh XhXh XHY XhY Colorblindness XCXC XCXc XcXc XCY XcY Sex Influenced Condition: not sex linked; not attached to the X chromosome; patterned baldness (influenced by female hormones) • Genetic Abnormalities: PKU: affects infants; lack an enzyme; problems with amino acids Sickle Cell Anemia: Pain at joints, fatigue; affects Black Americans; red blood cell shape of sickle; (1 in 500 is a carrier) Cystic Fibrosis: Caucasian disease; excess mucus during digestion Tay Sachs: Jewish infants (1 in 3 is a carrier) Galactosemia: problems with sugar breakdown Huntington’s Disease: causes insanity; dominant gene • Genetic Counseling: Sonagrams of fetuses Amniocentesis: technique in which amniotic fluid is extracted and examined Karyotype: a picture of the chromosomes Pedigree: a family history of genes • Genetic Engineering: Cloning/Gene splicing Human Genome Project “Green Revolution”