* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics Review: What is genetics? Genetics is what makes me
Cell-free fetal DNA wikipedia , lookup
Hardy–Weinberg principle wikipedia , lookup
Gene therapy wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Gene nomenclature wikipedia , lookup
Gene desert wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Genetic engineering wikipedia , lookup
Point mutation wikipedia , lookup
Genome evolution wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Gene expression profiling wikipedia , lookup
Y chromosome wikipedia , lookup
Neocentromere wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Genomic imprinting wikipedia , lookup
Gene expression programming wikipedia , lookup
Genome (book) wikipedia , lookup
History of genetic engineering wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
X-inactivation wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Genetics Review: What is genetics? ● Genetics is what makes me different from a tomato ● Heredity: transmission of traits from parent to offspring. Involves reproduction. ● Genetics explains the mechanism for variation that we see in organisms. Reproduction: ● Asexual ● Sexual: crossing of two organisms to make offspring. Way more variation. ○ A cell needs chromosomes they are normally distributed evenly between cells. Terms: ● ● ● ● ● ● ● ● ● ● ● ● Gene: a unit of hereditary information Traits: hereditary characteristics passed from parent to offspring. Pure: offspring that is always genetically identical to parents. P1 or P: parental generation, usually genetically pure to start ○ F1: first filial generation of offspring from mating two parents. ○ F2: second filial generation after self mating of F1. Dominant: a trait that dominates another factor or trait. Recessive: a trait that is dominated usually in the F1 of a heterozygous mating. Homozygous: Both alleles of a pair of homologous chromosomes are alike. Heterozygous: Two alleles in a pair of homologous chromosomes are different. Allele: each of several alternative forms of a gene on homologous chromosomes. ○ Lots of alleles are possible in one spot. Phenotype: a manifestation of genes. Appearance of organism due to traits expressed by a particular genotype. Genotype: the genetic makeup that is controlled by an organism’s alleles. Locus: the physical location of a gene on a chromosome. Mendel’s Laws: ● Law of Dominance: In a cross between two pure contrasting traits only one of these traits appears in the next generation. This is the dominant trait and the nonappearing one is recessive. ○ Best shown by TT x tt, the dominant trait is always the phenotype. ● Law of Independent Assortment: When dihybrid plants are crossed, the factor for each trait is distributed independently of factors for all other traits. ○ Traits do not influence each other. ○ Best illustrated by: AaBb x AaBb ○ Only applies if alleles are on different chromosomes exception is linkage. ● Law of Segregation: During gamete formation, the two genes responsible for each trait separate from each other so each gamete only contains one gene for each trait. ○ Explains the reappearance of recessive trait in the F2 after the F1 produces 100 percent dominant. ○ Best shown by Tt x Tt because the recessive phenotype shows up. ● Incomplete dominance: hybrid is different from both purebred parents. Theory of the Gene: 1. Genes in a chromosome are arranged in a row 2. Traits inherited together are located on the same chromosome. 3. Linkage groups may be broken by crossing over. 4. Position of genes on a chromosome may be determined. ● ● Non-sex chromosomes = autosomes Sex-linked inheritance: traits carried by sex chromosomes Chromosome Mutations: ● Ploidy: homologous chromosomes fail to separate resulting in diploid gametes. ● Nondisjunction: only one pair of homologous chromosomes fail to separate. Resulting gametes have an extra or missing chromosome. Fertilization of a “n” +with an “n” results in body cells with an extra chromosome. ● Causes of Gene Mutation: ● Xrays, radioactive isotopes, cosmic rays, other radiation, chemical mutagens. Factors Promoting Offspring Variation: ● Independent assortment of chromosomes, chance mating of different sperms/eggs, crossing over of different portions of chromatids, mutations. Why use the Statistical Method? ● Probability methods examine the formation of fertilized zygotes by gametes but look at the contribution of one trait at a time. This allows a consideration of many indirect non allelic loci in predicting genotypic outcomes. Most efficient way. Autosomal Recessive: ● A = Normal, unaffected ● a = NOT OK, affected ● A/anything = normal unaffected ● a/a = affected ● “Hidden potential” in carriers, healthy parents can pass to child Autosomal Dominant: ● A = NOT OK, affected ● a = Normal, unaffected ● A/anything = normal unaffected ● a/a = affected ● much easier to pass because only one allele needed, phenotype usually appears in every generation. X-Linked Recessive: ● XA= unaffected ● Xa = affected ● y=y ● XA XA= female unaffected ● Xa Xa = female affected ● XA Xa = female unaffected (carrier) ● XA Y = male unaffected ● Xa Y = male affected ● Fathers can’t pass to sons because mother carrier and affected father is only combination that yields affected female. X-Linked Dominant: ● XA= affected ● Xa = unaffected ● y=y ● XA XA= female affected ● Xa Xa = female unaffected ● XA Xa = female affected (carrier) ● XA Y = male affected ● Xa Y = male unaffected ● Gender specificity. Affected males don’t pass to sons. Affected females pass to half sons. Incomplete dominance: a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a combined phenotype. Codominance: A form of inheritance in which both alleles are equally shown. ● Good example of codominance is blood types. ○ IA/IA, IA/i = A blood type ○ IB/IB, IB/I = B blood type ○ IA/IB = AB blood type ○ i/i = O blood type Epistasis: one gene function stands upon another. 9:3:4: ● ● recessive epistasis: one product super cedes another in a pathway One recessive homozygous pairs phenotype overrides presentation of the other pair’s phenotype. ● A/_ B/_ will produce 9/16 phenotype for example (blue) ● ● A/_ b/b will produce 3/16 phenotype for example (magenta) a/a B/_ will produce 3/16 and a/a b/b will produce 1/16 of phenotype (white) ○ Even if B is there it wont’ be expressed because A supersedes it. 9:7: ● ● Both dominants at both loci bus t be there for pigment to be made. Involved gene products interact in the same pathway. Complementation of these genes allows certain phenotypes to be rescued by backup genes. ● A/_ B/_ will produce 9/16 phenotype. ● A/_ b/b, a/a B/_, and a/a b/b will produce the same phenotype. 12:3:1: ● ● ● ● ● The presence of a dominant gene prevents further events in a pathway. Two unlinked gene sets interact. A_/B_ and A_/bb produce 12/16 phenotype aa/B_ produces 3/16 phenotype. aa/bb produces 1/16 phenotype. Linked Genes: ● RF < 50 % = linkage ● RF >= 50 % = linkage is ruled out they must be on different chromosomes. ● 1 M.U. = RF OF 1% 5’ ATG GAC 3’ Sense DNA 3’ TAC CTG 5’ Antisense DNA (Sense to Anti = replication) 5’ AUG GAC 3’ mRNA (Antisense to mRNA = transcription) 3’ UAC CUG 5’ tRNA (mRNA to tRNA = translation) N MET ASP C (Protein made by ribosome) PCR: polymerase chain reaction. Simple amplification of DNA bounded by two target sequences. Temperature is key, also need heat stable polymerase. Griffith and Avery: Isolated DNA as element of heredity. Characterized its potential. Watson, Crick, Wilkins, Franklin: DNA structural characteristics. Beadle and Tatum: Central dogma, one gene = one polypeptide. Jacob and Monod: gene regulation, how DNA/Genes are controlled to express proteins. Chargaff: base pair rules