Study Guides (238,442)
Canada (115,138)
Biology (554)
BIO207H5 (39)

BIO 207 Final Exam Reviews.docx

7 Pages
Unlock Document

University of Toronto Mississauga
Fiona Rawle

CH 14 Evolutionary genetics examines genetic changes in populations and species over time Lossoffunction mutations that produce no functional gene product is called a null mutation or amorphic mutation often these are lethal when homozygous Lossoffunction mutations that result in a partial loss of function are called leaky mutations or hypomorphic mutations the severity of the phenotype of these depends on the level of activity of the leaky mutation Hypermorphic mutations produce more gene activity than normal Neomorphic mutations acquire novel gene activities not found in the wild type Replicate crosses producing hundreds or thousands of progeny by repeating each cross several times Reciprocal crossesthe same genotypes are crossed but the sexes of the parents are reversedMonohybird 34 domin 14recess Dihybird 916 both dom 316 one domone recess 316 other domress 116 both recess Trihybird the progeny will be expressed as sixtyfourths Dominant Recessive refer to phenotypes affected by alternative alleles at a single genetics locus Recessive phenotype is observed only in the homozygote gg Dominant phenotype is observed in heterozygote homozygous GGGg lethal allele is often detected as a distortion in segregation ratios where one class of expected progeny is missing If the alleles are epistatic you would see less than 4 different phenotypes in the F2 progeny and a modification to the 9331 ratio CH 5 Genetic linkage identifies genes that are so close to one another on a chromosome that their alleles do not assort independently With genetic linkage parental combinations at frequencies that are significantly greater than those predicted by chance and nonparent recombinant ions are much less frequent than expected Complete genetic linkage has no crossing over occurs between linked genes only parental gametes are formed Incomplete genetic linkage is more common than complete linkage it produces a mixture of parental and nonparental gametes The two parental types are approx equal in frequency as the two recombinant typesof recombinant gametesrRecombination frequency reflects the physical distance totalof meiosesbetween two genes Crossing over occurs at a higher rate between genes that are farther apart Linked genes with higher recombination frequencies are more distant from one another than genes with lower frequencies Syntenic genes separated by less than 50mu will show the genetic linkage Separated by 50mu or more will assort independently and there will be one or more crossovers between them per meiosis Finding the Relative Order of Genes by ThreePoint Mapping In a cross between a trihybrid individual and one homozygous recessive for all three genes the gene configuration need not be known in advance Incomplete linkage produces eight different gamete genotypes with unequal frequencies if the genes are linked Parental types will be observed most frequently the recombinant types less frequently Parental gametes are
More Less

Related notes for BIO207H5

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.