Diversity and Adaptation can be explained through Evolution

Diversity and Adaptation can be explained through Evolution: change in the form and behavior of organisms between generations within a population of a species. Natural Selection: The process by which the forms of organisms in a population that are best adapted to the environment increase in frequency relative to less well adapted forms over a number of generations One Population Generation 1 Generation 2 Generation x Extinct Generation z

Diversity and Adaptation can be explained through Evolution: change in the form and behavior of organisms between generations within a population of a species. Natural Selection: The process by which the forms of organisms in a population that are best adapted to the environment increase in frequency relative to less well adapted forms over a number of generations One Population Favorable trait How was it passed on? Generation 1 Generation 2

Diversity and Adaptation can be explained through Evolution Fact 1: organisms within a population vary (in size, forms, behavior, etc. ) Fact 2: these variable traits can be passed to the offsprings (are heritable) HOW? ? ? One Population Generation 1 Generation 2 Generation x Extinct Generation z

Mendelian and non-mendelian genetics

Genetics: study of genes, genetic variation, and heredity Gregor Mendel (1822 -1884) Austrian Scientist, Abbot in Brno Founder of the Science of Genetics Experiments in Plant Hybridization (1865) Studied patterns of inheritance in peas Established laws of Heredity

Genetics: study of genes, genetic variation, and heredity Monohybrid cross (1 phenotypic trait) ~ 1000 plants/experiment P F True-breeding plants Hybrid plants F 1 Uniform F 2 Ration 3: 1 No blending! F 1 carries information for white flower, but it is invisible!

Genetics: study of genes, genetic variation, and heredity Monohybrid cross (1 phenotypic trait) ~ 1000 plants P True-breeds F 1 Uniform F 2 Ration 3: 1 Dominant trait: form of trait that will appear in the offspring if one of the parents contributes it. Recessive trait: form of trait that is carried but not always visible (dominated by other form of the trait).

Genetics: study of genes, genetic variation, and heredity Monohybrid cross (1 phenotypic trait) ~ 1000 plants P True-breeds F 1 Uniform F 2 Ration 3: 1 Phenotype: externally observed makeup of an organism Genotype: internal (genetic) makeup of an organism

Genetics: study of genes, genetic variation, and heredity Gene locus: position of a gene on a chromosome Gene: portion of the DNA that encodes a function; basic unit of heredity Allele: alternative forms of a gene

Genetics: study of genes, genetic variation, and heredity Gamete: male or female germ cells, that are Haploid: 1 set of chromosomes (n) Zygote: first cell of organism after fertilization. Diploid: 2 sets of chromosomes (2 n)

Genetics: study of genes, genetic variation, and heredity Gene: flower color 2 Alleles (gene forms): Dominant allele (purple): P (CAPITAL) Recessive allele (white): p (small)

Genetics: study of genes, genetic variation, and heredity Gene: flower color 2 Alleles (gene forms): Dominant allele (purple): P (CAPITAL) Recessive allele (white): p (small) Organism is: Homozygous: PP and pp (true-breeds) Heterozygous: Pp (Hybrids)

Genetics: study of genes, genetic variation, and heredity Gene: flower color PP pp 2 Alleles (gene forms): Dominant allele (purple): P (CAPITAL) Pp Recessive allele (white): p (small) Organism is: PP Homozygous: PP and pp (true-breeds) Heterozygous: Pp (Hybrids) Pp Pp pp

Genetics: study of genes, genetic variation, and heredity Parent generation Genetic makeup: PP pp Gametes: P p Pp Homozygous Heterozygous

Genetics: study of genes, genetic variation, and heredity Parent generation Genetic makeup: PP pp Gametes: P p Pp Genetic makeup: F 1 after cross Gametes: ½ P ½ p Homozygous Heterozygous

Genetics: study of genes, genetic variation, and heredity Parent generation Genetic makeup: PP pp Gametes: P p Pp Genetic makeup: Homozygous Heterozygous F 1 after cross ½ P Gametes: ½ p sperm from F 1 Gametes: F 2 after self pollination eggs from F 1 P p P PP Pp pp Punnet square

Genetics: study of genes, genetic variation, and heredity Parent generation Genetic makeup: PP pp Gametes: P p Pp Genetic makeup: Homozygous Heterozygous F 1 after cross ½ P Gametes: ½ p sperm from F 1 P p Punnet square P PP Pp Phenotype: 3: 1 p Pp pp Genotype: 1: 2: 1 Gametes: F 2 after self pollination eggs from F 1

Genetics: study of genes, genetic variation, and heredity Variations on the Law of Dominance 1) Complete Dominance: recessive alleles will be masked by dominant alleles 2) Incomplete Dominance: dominant allele not fully expressed.

Genetics: study of genes, genetic variation, and heredity Variations on the Law of Dominance 1) Complete Dominance: recessive alleles will be masked by dominant alleles 2) Incomplete Dominance: dominant allele not fully expressed. Phenotype ratios = Genotype Ratios 3) Co-Dominance: two or more alleles are dominant and both are expressed 4) Pleiotropy: one gene controls expression of several traits/ phenotypes 5) Quantitative inheritance: one trait is controlled by more than one gene and is the cumulative action of many genes --- Height, weight, intelligence

One-gene disease • Disease caused by mutation in one gene • Sickle cell anemia (autosomal recessive) – Chromosome number 11, gene called HBB – SS homozygous dominant – No trait – Ss Heterozygous – ‘Carrier’ – Ss homozygous recessive – disease

• At the genome level • At the protein level • The phenotype https: //evolution. berkeley. edu/evolibrary/article/0_0_0/mutations_06

How did this come about - Adaptation to Malaria - Beneficial to have the trait as it confers a high degree of resistance to severe and complicated malaria - More carriers = greater chance of carriers mating - Sickle cell disease

Homework • Draw punnet squares for – SS x SS – Ss x ss – ss x ss • Elaborate on disease % in children

Huntington’s disease • Autosomal dominant • Chromosome 4, HTT gene – CAG triplet repeat number in exon 1 of huntingtin (HTT) gene

Homework • Draw the punnet square of – Dd x Dd – Dd x DD – DD x DD – dd x dd • Elaborate on disease % in children

Gender-linked Inheritance • Genes on the X and Y chromosomes • Female: • XAXa = carrier of recessive trait • Male: • XAY = only one allele for trait • e. g. Hemophilia

http: //christensengen 677 s 13. weebly. com/

Y-linked inheritance • Far fewer diseases that are Y-linked • Y – chromosome is smaller and encodes less information • Y- linked are passed from father to son, not usually found in females