* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics and Heredity
Pathogenomics wikipedia , lookup
Minimal genome wikipedia , lookup
Population genetics wikipedia , lookup
Ridge (biology) wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Copy-number variation wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Point mutation wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
X-inactivation wikipedia , lookup
Epigenetics of neurodegenerative diseases wikipedia , lookup
Genetic engineering wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Genomic imprinting wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Public health genomics wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Genome evolution wikipedia , lookup
History of genetic engineering wikipedia , lookup
Gene therapy wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Helitron (biology) wikipedia , lookup
The Selfish Gene wikipedia , lookup
Gene desert wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Gene nomenclature wikipedia , lookup
Gene expression programming wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Genome (book) wikipedia , lookup
Gene expression profiling wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Genetics Gregor Mendel– the “father” of genetics A genetic characteristic generally has two (or more) possible varieties– known as traits. Ex. Plant height: long or short. Flower color: purple or white Along every chromosome, each specific location contains a specific gene for a specific characteristic. Different varieties of each gene are called alleles. Genes exist in pairs, like chromosomes. For every characteristic, you have two genes that determine how that characteristic will appear. The dominant allele of the gene almost always completely masks the recessive allele of the gene. Genotype: the combination of genes that the organism has Phenotype: the actual appearance of the organism Heterozygous: when the two alleles are different Homozygous: when the two alleles are the same If the pea plant is purple, purple is dominant over white in flower color. Could be PP (homozygous dominant) or Pp (heterozygous). If the pea plant is white, it must be pp (Homozygous recessive). Exceptions to “normal” scenarios of inheritance Incomplete dominance: in the heterozygous genotype, the dominant allele does not completely mask the recessive Co-dominance: in the heterozygous genotype, two alleles are visible in the phenotype at the same time Epistasis: one gene modifies the appearance of another gene Incomplete dominance Codominance Sex-linked traits • The gene is usually located on the xchromosome. • Sex-linked traits are most common in males. • Usually passed from mother to son. • Female carriers get one gene from either mother or father. • Examples: Colorblindness, hemophilia, Duchenne Muscular Dystrophy Alternative Patterns of Heredity ( in addition to incomplete dominance, codominance, and multiple alleles) • Epistasis– a gene at one locus alters the expression of a separate gene • Pleiotropy– a gene with multiple phenotypic effects • Polygenic inheritance– an additive effect of two or more genes on a single phenotype epistasis Fur pigment color B= black (complete) b= brown Pigment deposition gene C= pigment deposited c= pigment NOT deposited The pigment deposition gene is epistatic to the pigment color gene. Pleiotropy • Cystic fibrosis– one gene codes for a defective protein in certain cell membranes; causes multiple effects: thicker & stickier mucus membranes, poor nutrient absorption, chronic bronchitis, recurrent bacterial infections • Sickle-cell disease– one gene for a single amino acid is altered in the hemoglobin molecule; causes multiple effects: blood clots, physical weakness, pain, organ damage, paralysis, lowered blood oxygen, brain damage Polygenic inheritance (simplified) 3 pairs of genes determine skin color and the combination of those genes determine the phenotype. The more dominant genes, the darker the skin. Sample question: describe the pattern of inheritance of Huntington’s disease. • Dominant, autosomal, lethal (presents at relatively older age, so inheritance is possible in younger generations) • Any child born to a parent with Huntington’s has a 50% chance of inheriting the gene