Textbook Notes (362,734)
Canada (158,032)
Biology (27)
BIOL 2000 (3)
Chapter 3

Chapter 3.docx

3 Pages
Unlock Document

University of Lethbridge
BIOL 2000
Joseph Rasmussen

Chapter 3 Independent Assortment of Genes Definitions  Mendel’s second law- During meiosis, alleles at one gene pair segregate independently of alleles of a second gene pair  Dihybrid- an individual heterozygous at two genes  Product rule- the probability that two independent events occur together is equal to the product of their individual probabilities  Sum rule- the probability that either of two mutually exclusive events occurs is equal to the sum of their individual probabilities  Recombinant- a Meiotic output of different genotype than the meiotic input  Parental- meiotic output of the same genotype as the meiotic input  Ascis- a sac that encloses the products of meiosis (ascosproes) in some fungi  Maternal inheritance- inheritance pattern displayed by a gene on an organelle genome (chloroplast or mitochondria); offspring have maternal phenotype and genotype The green revolution in agriculture  Rice, wheat and corn that are shorter, disease resistant  Norman Borlaug- greatest man of the 20 century, awarded Nobel Peace Prize thought to have saved lives of a billion people Mendel’s law of independent assortment  Mendel studied seven phenotypic pairs  What happens if pair of traits are considered together?  Mednel crossed round green seeded individuals (R/r.y/y) by winkled yellow individuals (r/r.Y/Y) ( “.” Indicated gene location unknown)  F1 individuals show dominant traits for both characters- they are heterozygous at both genes o R/r.Y/y= dihybrid  Deriving 9:3:3:1 using a Punnett square  If genes segregate independently of one another, what gametes do we expect and in what frequencies? o ¼ R.Y o ¼ R.y o ¼ r.Y o ¼ r.y  Punnett’s square predicts that random fusion of four gamete types will give rise to a 9:3:3:1 ratio Mendel’s second law  During gamete formation, the segregation of alleles of one gene is independent of the segregation of the alleles of another gene  The product rile predicts 9:3:3:1 ratio from two independent monohybrid (3:1) ratios o Using a branch diagram to derive 9:3:3:1 Test-crossing a dihybrid  Y/y.R/r x y/y.r/r  If a dihybrid is testcrossed, expect the frequency of phenotypes in the test cross progeny to reflect the gamete frequency of the dihybrid  Calculating genotypic ratios: o Genotype rato for F2 of a dihybrid will be 1:2:1 x1:2:1= 1:2:1:2:4:2:1:2:1  Calculating individual probabilities o If only one fusion even results in a particular genotype  Use product rule: the probability of independent events is the product of their individual probabilities  P(yyrr) = ¼ x ¼ = 1/16 o If more then one fusion event results in a particular genotype  Apply both product rule and sum rule  Sum rule: The probability of either of two mutually exclusive events occurring is the sum of their individual probabilities 
More Less

Related notes for BIOL 2000

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.