BS 162 1st Edition Lecture 6 Ploidy and Meiosis PLUS QUIZ REVIEW Diploid A cell with two copies of each chromosome a homologous pair of each chromosome 2n 46 Haploid A cell with only one copy of each chromosome n 23 Phenotype physical manifestation of genes Genotype genetic code or allele for the gene Gametes egg sperm only have one copy of each chromosome so when they combine their child has the correct amount 2 copies 2n diploid 46 1 copy n haploid 23 Meiosis where gametes are formed and number of chromosomes is reduced from 2n to n diploid to haploid Chromosomes line up next In example 2 different to each other Chromosomes replicate connected with centromere and then are divided via meiosis These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Tetrads replicated chromosomes that line up side by side during meiosis Crossing over sections of DNA that are swapped when tetrads are formed Review for quiz Thursday This is taken from Quiz 1 a few years ago It should help you apply the concepts of hypothesis testing and claims evidence warrants to a human genetics problem It should also help you model chromosomes and apply your genetics vocabulary CASE Familial hypercholesterolemia FH is a genetic disease that leads to a dramatic increase in LDL low density lipoprotein cholesterol Individuals with the disease have LDL levels that are twice normal by the age of two and their risk of early onset for coronary artery disease heart attack is elevated by about 20 times The prevalence of FH is 1 in 300 to 500 in general populations In some populations such as French Canadians and Dutch Afrikaners the prevalence of FH is near 1 in 100 The low density lipoprotein receptor gene LDLR is responsible for many of the cases of FH The LDLR gene is located on the short arm of chromosome 19 and spans 4500 base pairs with the resulting protein containing 839 amino acids The normal allele of LDLR allele R produces proteins in the liver which function normally and destroy low density lipoproteins The mutated allele of LDLR allele r produces proteins in the liver which do not bind properly to the low density lipids that normally would be destroyed thereby increasing the LDLs in the bloodstream Since individuals have 2 copies of chromosome 19 an individual person will either have the alleles RR Rr or rr Only individuals that are rr have the disease Question 1 Researchers Michael S Brown and Joseph L Goldstein won the Nobel Prize in 1985 for discovering the gene LDLR that causes FH Write the null hypothesis and the alternative hypothesis that was being tested by these Nobel prize winners in their study from which they concluded that the mutated LDLR gene caused FH Question 2 Draw one chromosome 19 using the stick model Show and label the location locus of the LDLR gene not allele Question 3 Draw the chromosomes 19 before DNA replication for an individual who is heterozygous for the LDLR gene In your drawings label the following structures if they are present LDLR alleles centromeres homologous chromosomes and sister chromatids Question 4 Draw a nucleus during metaphase of mitosis before cell division for an individual who is heterozygous for the LDLR gene Label all the structures mentioned in Q3 if present Question 5 When the nucleotides that code for the alleles R and r are expressed as proteins will the amino acid sequences be identical Please clearly state YES or NO and then explain why or why not in 1 sentence Now that there is a test for the mutated allele people who are in high risk groups for FH can be genetically tested to see which alleles they carry A group of physicians at the Mayo clinic feels that they can help individuals with FH live longer by helping them change their lifestyle and diet to deal with the disease In order to test this researchers at MSU performed an experiment to determine whether people tested positive for the allele for FH and then took preventative measures by changing their lifestyle would avoid the early death associated with the disease The results are shown in the bar graph below Question 6 What is the claim of the individuals at the Mayo clinic Question 7 Does the evidence shown in Figure 1 support the claim from Q6 Clearly explain WHY or WHY NOT in 1 or 2 sentences Question 8 What would a warrant be to support the claim and evidence above If you don t feel you have enough information provided on this quiz for a warrant feel free to come up with an example that you make up Figure 1 The percentage incidence of an early death from cardiovascular disease among three groups 1 individuals that were FH positive but were never tested 2 individual that were FH positive were tested and took preventative measures and 3 individuals that were FH negative Take note of this wonderful figure legend Would you have been able to write something this good Remember this figure legend doesn t say FH positive people that took preventative measures live longer Let each person who looks at it decide that for his herself Questions to ask yourself Can you read a blurb and come up with a null and alternative hypothesis Can you read about an experiment that was done and critique it and or decide what the claim evidence and warrant are for the experiment Can you come up with an experiment to test some hypotheses Can you draw a graph using either continuous or categorical data Label it properly with axis labels legend Could you draw data with a high r2 value low r2 value high variance Low variance Can you interpret data shown in a graph or table form to decide which hypothesis it would support Can you draw a stick model of DNA Can you label the various structures genes alleles centromeres chromatids Can you draw a nucleotide base model of DNA Could you represent a SNP Can you determine a person s phenotype given their genotype and vice versa Can you organize genetic information from smallest to largest Do you understand what a gene codes for and how different versions of the gene change the protein and affect an organism Can you draw chromosomes before and after DNA replication and mitosis Can you determine the products of mitosis