WELCOME to Bio 230: Genetics Dr. Erin Gestl Jan 24 Pages 1-28

On-line Resources http://darwin.wcupa.edu/faculty/gestl Syllabus Powerpoint Lectures

TEXTBOOK Introduction to Genetic Analysis 11TH EDITION Griffiths • Wessler • Carroll • Doebley

Quiz 1 Name Major List three things you know about genetics. List three things that are controversial (in the news) concerning genetics. List three things you hope to learn in class. #3 Imagine you are a geneticist in the future….what could you be working on addressing food shortages by genetically modifying plants to make them resistant to fungal infections determining which single nucleotide polymorphisms are associated with human disorders investigating which genes are involved in mammalian development from conception to birth searching for mutations in genes that result in human diseases

Discuss as a class So what are some controversial topics in genetics? What would you most like to learn?

Chapter 1: Genetics Revolution Genetics – Study of inheritance

Genetic Inheritance Originally purposed as the Blending theory Red x white flowers = pink flowers Tall person x short person = average height person It became clear very quickly this was not how nature worked

Mendel and his peas Gregor Mendel– 1863 Proposed Mendel’s particles not fluid (which are now called genes) Peas had two copies of each gene in plant body (somatic cells) and only one copy in sex cells (gametes) Introduced dominant vs recessive alleles Explained why Pink x Pink flowers yield white and red flowers

Complex Traits Single-Gene Traits Red x white flowers = pink flower Person’s height

Mendel’s law of Equal Segregation During the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent Hereditary factors are called genes Diploids have two copies of each gene Genes come in different forms called alleles Capital letter (A) allele is dominant, a is recessive Members of a gene pair (Aa) separate equally into gamete

One of Mendel’s experiments

Model Organisms A species used in experimental biology with the presumption that what is learned will hold true for other species. Characteristics Easy and inexpensive to maintain Short generation time Very simple to cross/mate Produce ample numbers of offspring Well suited to answer a scientific question

Model Organisms in Genetics What makes a model organism a “model” organism? What features are key? Easy and inexpensive to maintain Short generation time Very simple to cross/mate Produce ample numbers of offspring

Genetics Today Farmers grow rice using controlled flooding Problem: In poverty areas water is not well regulated and the can kill the rice if it remains flooded 1. that is, individuals with a particular characteristic may reproduce better than others in a given environment. 2. (i.e., mutations). 3. Charles Darwin proposed that evolution occurred through the process of natural selection.

Genetics Today A submerged resistant strain was identified, but it had a poor yield Solution: Cross the 2 strains to create a strain that is both high yield and submerged resistant American Chestnut 1. that is, individuals with a particular characteristic may reproduce better than others in a given environment. 2. (i.e., mutations). 3. Charles Darwin proposed that evolution occurred through the process of natural selection.

Genetics and Evolution Evolution depends on natural selection Evolution depends on genetic variation Who purposed evolution occurs through natural selection? For evolution to occur, allele frequencies in a population must change over several generations. Gene variants arise from mutations 1. that is, individuals with a particular characteristic may reproduce better than others in a given environment. 2. (i.e., mutations). 3. Charles Darwin proposed that evolution occurred through the process of natural selection.

Single Nucleotide Polymorphisms SNPs -a DNA nucleotide variation occurring in the genome between two members of the same species

Occurrance in Humans -1 in 1000 bases, 0.1% -3 to 10 million SNPs in the human genome

How does genetics influence our diet? Any examples? Celiac Disease Can not digest gluten (lack the enzyme) Yes this is Hereditary (Genetics) This is different than “gluten intolerant” Lactose intolerance Lack Lactase enzyme to digest the sugar found in dairy known as lactose

Genetics associate with diet T variant have persistent expression of the lactase gene into adulthood C variant have their lactase gene switched off after childhood (lactose intolerant) A protein called OCT1 can bind to the T variant and turn on lactase gene expression Single nucleotide polymorphisms can be used to determine in which parental germ line (i.e., in egg cells or sperm cells) a new point mutation occurred. Some human populations have lactase gene variants expressed in adults People with the T variant have persistent expression of the lactase gene into adulthood, where as people with the C variant have their lactase gene switched off after childhood

Review Question Which of the following traits is not ideal for a model organism? Easy and inexpensive to maintain Short generation time A large complex genome that allows for the creation of billions of possible mutations Very simple to cross/mate and produce ample numbers of offspring even though you my only need a couple progeny per project

In the news…. The octopus genome and the evolution of cephalopod neural and morphological novelties (Albertin et al., 2015) https://www.youtube.com/watch?v=634j7m5U5II What is something you learned from this video?