* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Genetics - My Teacher Pages
Oncogenomics wikipedia , lookup
Heritability of IQ wikipedia , lookup
Gene therapy wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Genetic engineering wikipedia , lookup
Hardy–Weinberg principle wikipedia , lookup
Point mutation wikipedia , lookup
Gene expression programming wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Ridge (biology) wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Genome evolution wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Minimal genome wikipedia , lookup
Genomic imprinting wikipedia , lookup
X-inactivation wikipedia , lookup
Genome (book) wikipedia , lookup
History of genetic engineering wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Gene expression profiling wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Microevolution wikipedia , lookup
Quantitative trait locus wikipedia , lookup
GENETICS IN A NUTSHELL THE BASICS Dominant: represented by a large letter; trait that is expressed Recessive: represented by a small letter; trait that is masked unless in the homozygous form Genotype: genes in an organism Phenotype: outer appearance from the genes MORE BASICS Living things are made of millions of tiny self-contained components called cells. Inside these cells are long and complex molecules called DNA DNA stores information that tells the cells how to create that living being. Parts of this information that tell how to make one small part or characteristic of the living thing – red hair, or blue eyes, or a tendency to be tall – are known as genes. MORE BASICS Every cell in the same living thing has the same DNA, but only some of it is used in each cell. For instance, some genes that tell how to make parts of the liver are switched off in the brain. What genes are used can also change over time. MORE BASICS A living thing has two copies of each gene, one from its mother, and one from its father. There can be multiple types of each gene, which give different instructions: one version might cause a person to have blue eyes, another might cause them to have brown. Alleles These different versions are known as alleles of the gene. Alleles Since a living thing has two copies of each gene, it can have two different alleles of it at the same time. Often, one allele will be dominant, meaning that the living thing looks and acts as if it had only that one allele. Alleles The unexpressed allele is called recessive. In other cases, you end up with something in between the two possibilities. In that case the two alleles are called co-dominant. BASICS Most of the characteristics that you can see in a living thing have multiple genes that influence them. Many genes have multiple effects on the body, because their function will not have the same effect in each tissue. MORE BASICS The multiple effects of a single gene is called pleiotropism. The whole set of genes is called the genotype. The total effect of genes on the body is called the phenotype. MORE BASICS AA=homozygous dominant Aa=heterozygous aa=homozygous recessive AA or Aa=dominant trait aa=recessive trait Autosomal Trait An autosome is a gene found in the body cells, i.e. not found on sex chromosomes. Genetics follow basic heredity rules regarding dominance and recessiveness. Combine TT (homozygous tall) and Tt (heterozygous tall)…What do you get? Welcome the Punnett Square A Punnett Square explains the possible outcomes for a mating. T T T TT TT t Tt Tt So… A cross between a homozygous tall and a heterozygous tall would yield… – 50% probability of getting homozygous tall plants as offspring – 50% probability of getting heterozygous tall plants as offspring HOW do you get a short plant? Well… Either cross tt x tt or Tt and tt Try the Punnett Square for each… T t t t Sex-Linked Trait on a gene found on X or Y chromosome Usually are recessive disordersapparent only in the homozygous recessive form Common example: red-green colorblindness in boys or hemophilia Sex-Linked Trait Notation Notation: – – – – – Male with trait: XhY Male without trait: XHY Female with trait: XhXh Female without trait: XHXH Carrier female: XHXh TRY ONE: Cross a hemophiliac male and a carrier female. Incomplete Dominance Autosomal traits BUT the heterozygous phenotype is a combination of the two homozygous phenotypes Example: Color in snapdragons – RR=red – Rr=pink – rr=white TRY ONE: Cross a pink snapdragon with a red flower. Co-dominance Autosomal traits BUT the heterozygous is BOTH homozygous traits. NO RECESSIVE Example: Horse Coloring – RR=Red – RR’=Red/White (Roan) – R’R’=White TRY ONE: Cross a two roan horses. Blood Types Combination of Co-dominance and dominant and recessive patterns – AB blood: IA IB – A blood: IA IA or IA i – B blood: IB IB or IB i – O blood: ii TRY ONE: Cross a heterozygous A blood female with a homozygous B blood male.