BIOLOGY 111 1st Edition Lecture 18 Outline of Last Lecture I. Epistasis II. Pedigree AnalysisIII. Inherited Disorders in HumansIV. Chromosome Theory of Inheritance Outline of Current Lecture I. Parental Type OffspringII. Recombinant Type OffspringIII. Frequency of RecombinationIV. Linkage MapV. Alteration of ChromosomeVI. Epigenetics Current Lecture- Parental type offspring - resemble the parents- Recombinant offspring - result of crossing over (in Meiosis 1)- On the same chromosome - if there is no crossing overo all offspring are expected to match their parental types- if there is crossing over in Meiosis 1 (no crossing over occurs in Meiosis 2)o Parental type will be 50%o Recombinant type will be 50%- if there are three genes on the same chromosomeo parental type will be most commono recombinant will be intermediate o double recombinant will be the least amount - Frequency of Recombination (how many times you will see a cross over) o if on different chromosomes, they are 50/50o if on same chromosome, use equation below  ( recombinants / total offspring ) * 100 = recombination frequency- linkage map (a genetic map based on recombination frequency)o the closer the genes are, the less frequently they will recombine  ex. 1 map unit = 1% recombination frequencyo the further the genes are, the more likely they will cross overThese 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. ex. 10 map units = 10% recombination frequencyo maximum recombination frequency = 50 map units  you will not exceed 50 map units, if you calculate 50 map units, they are not on the same chromosome, therefore, they are not linked  if they are on the same chromosome, they will behave like unlinked genes even though they're on the same chromosome less than 50 map units, they are linked - Alteration of chromosome structure (occurs during cell division)o deletion - removes a chromosomal segment, a small piece of DNA is deleted, whatever it was coding for, you lose that functiono duplication - repeats a segment o inversion - reverses a segment within a chromosome o reciprocal translocation - switching with other chromosomes, movement of a segment from one chromosome to a nonhomologous chromosome.  most often a nonhomologous chromosome exchanges fragments less often a nonreciprocal translocation occurs, a chromosome transfers a fragment but receives none in return - Translocations can move a gene to a new location and place it under control of different regulatory regions (during mitosis)- Chromosome number and alterations o polyploid - 3 or more sets of chromosomes  diploid 2n, triploid 3n, tetraploid 4no aneuploidy - all abnormal chromosome numbers (causing developmental and genetic abnormalities)- nondisjunction - members of a pair of homologous chromosomes do not move apart properly during meiosis 1 or meiosis 2 o autosomal  Trisonomy 21 (Down syndrome) Trisonomy 18 (Edward syndrome) Trisonomy 13 (Patau syndrome) o sex chromosome  XXY (Klinefelter) XYY (Jacobs) XXX (Triple X) XO (Turner)- Epigenetics o Genomic Imprinting - occurs when the phenotype exhibited by a particular allele depends on which parent contributed the allele to the offspring it causes genes from one parent to be temporarily silent during early development by DNA packaging or methylation (not mutation) silence = imprinted with a tag (that says do not present yourself) tags attach to certain types of genes, these tags are what silent or activate a gene (these tags are reversible)- silents a gene by adding methyl groups (CH3)- or they can change the histones (proteins)o if they tightly wind them, expressing is suppressedo loosely wound, more expression  the phenotype changes accordingly to which genes are activated and which are silenced - the phenotype depends on the male and female parents o ex. a specific partial deletion of chromosome 15  prader-willis syndrome (from the father) angelman syndrom (from the mother)- cytomplasmic genes (in mitochondira and chloroplasts)o inherited only through the maternal linkage (all mitochondrial DNA came from the mother)o the sperm has mitochondria but its purpose is to create enough ATP to function the flagella to get to the eggo mitochondrial Diseases Lebers Neurogenic 