01:119:100 Lecture Notes - Lecture 24: Mendelian Inheritance, Punnett Square, Dihybrid Cross

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amethystshark595

12 Jul 2015

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Using probability to predict mendelian inheritance: genetic ratios are expressed in probabilities, probability of an even is its expected frequencies. Ex: frequency, . 75 frequency, or 75: certain to occur probability is one, if certain that it will not occur then probability of expected frequency is 0, punnett square allows two of more probabilities to be combined. Aa x aa gametes produced is aa, a a a a. 1/4 aa, aa, 1/4aa, 1/4aa 3dominant:1recessive: probability of all possibilities sum to one p(dominant)=3/4, p(recessive)=1/4, product rule predicts combined probabilities of independent events, Independent event means the occurrence of one event does not affect the probability that other event will occur. P(this) and p(that) and means that you multiply separate probabilities: ex: coin toss, what is the probability of tossing 2 heads? (one head and another) P(1st child could be aa and 2nd child aa) = p(1st aa) and p(2nd aa) * = 1/16: sum rule predicts combined probabilities of mutually excluve events.

Related Questions

1.) This summer, there was a surge in the number of albino children killed for their body parts in the African country of Malawi (yes, it's bizarre but sadly true: http://goo.gl/8o0imm and http://goo.gl/DK0r8M). Albinism in humans is inherited as a simple recessive trait. Assuming that two non-albino (normal) parents have five children, four of which are normal and one of which is albino, which of the following statements is true? Select all that apply (you must select all correct answers to get credit). Assume that 'A' indicates the non-albino allele and 'a' indicates the albino allele.

Multiple answers:You can select more than one option

A)The 4 normal children are heterozygous Aa

B)At least one of the normal siblings must be homozygous AA

C)The frequency of albino children is as expected for Mendelian inheritance

D)One of the parents cannot be Aa

E)One third of the normal children expected to be AA while the others Aa

2.)

Albinism in humans is inherited as a simple recessive trait. Assuming that a normal male and an albino female have 6 children, all normal, which of the following statements is true? Select all that apply (you must select all correct answers to get credit).

Multiple answers:You can select more than one option

A)The father could be heterzygous for the trait

B)The probability that all the children are heterozygous for the trait is (1/2)^5 = 1/32

C)The father cannot be Aa

D)The children should all be heterozygous for the trait

E)One would expect about 2/3 of the normal children to be Aa

F)The father must be AA

3.)

Given an albino male mating with a normal female to produce 3 normal children and 3 albino children, which of the following of Mendel's postulates are not being demonstrated by this particular scenario? Select all that apply (to get credit, all your choices must be correct).

Multiple answers:You can select more than one option

A)Postulate of segregation

B)Postulate of dominance

C)Postulate of independent assortment

D)Postulate of unit factors

4.)

Consider the cross: Ee ff Gg HH x Ee Ff gg HH (assume these are designations for genes that are inherited in a Mendelian fashion). What is the probability that a single offspring from this cross would be genotypically: ee Ff Gg HH or Ee ff gg HH?

A)1/16

B)1/32

C)9/64

D)1/6

E)3/16

F)27/64

G)1/64

H)3/64

I)1/8

J)3/8

1) Which of these probabilities are NOT independent of eachother?

The probability that a student is a sophomore and has brownhair

The probability that when you roll two dice, you will roll a 6before a 2

The probability that it will rain and the probability ofneeding an umbrella

The probability that there will be heavy traffic on BaltimoreAve and the probability you will lose your cell phone

2) We are defining evolution as a "change in allele frequenciesover time". Ironically, the focus of this lab is the Hardy-Weinbergequilibrium - conditions that, if all met, will result in NOevolution occurring. Which of the following are among theconditions that must be met for the Hardy-Weinberg equilibrium toapply perfectly to a population?

A. The population must be very large

B. Individuals must mate at random

C. The alleles must differ in their effects on survival

D. There must be free migration into and out of thepopulation

A & B

A, B, & C

3)In cats, black fur is dominant over any allele for brown fur.If a homozygous dominant cat makes kittens with a heterozygous cat,what is the probability that the first kitten will have brown fur?Report as a proportion, not percentage, e.g., .1, NOT 10%.

The EGLN1 gene helps regulate body oxygen levels. One allele His dominant over h, and helps increase fitness at high altitude(where oxygen is low). In a study of families in Tibet, researchersfound 422 HH individuals, 377 Hh, and 201 hh individuals. The studyshowed that infant mortality was lower in Hh individuals than hh,and lowest in HH individuals.
Is the Tibetan population in Hardy Weinberg Equilibrium at this H/hgene?

What is the most important factor affecting the strength ofgenetic drift?

The frequency of the rarest genotype

The size of the population

The allele frequencies

The genetic diversity in the population

aquamarinerat250

1 A) Cystic Fibrosis is an autosomal recessive disease, 1 out of every 2500 individuals of Caucasian descent in the US have cystic fibrosis. What frequency of cystic fibrosis carriers would you expect in the Caucasian population of the US under Hardy Weinberg Equilibrium? Show your work. (1 pt)

1 B) You know that penguin tuxedo color is a classic Mendelian single-gene trait, the allele for black and white tux coloring (T) is dominant over gray and white tux coloring (t). In a population of penguins, there are 400 black and white tuxedoed penguins and 200 gray and white tuxedoed penguins.

(i) Which observed genotypic or allelic frequencies can be calculated from this scenario without assuming Hardy Weinberg Equilibrium? (1.5 pt)

(ii) In one to two sentences, explain why differences may arise between observed and expected genotype frequencies. (1 pt)

1 C) You are studying inheritance of external keratin features in a dinosaur. Analysis has found that the presence of feathers is due to codominance between the AS (scales) and AH (horns) alleles. In one generation of a population you find 78 scaled dinosaurs, 76 feathered dinosaurs, and 64 horned dinosaurs.

(i) What are the observed allele frequencies of AS and AH ? Use p for the frequency of AS and q for the frequency of AH . Show your work. (1.5 pt)

(ii) What are the observed genotypic frequencies? Show your work. (1 pt)

(iii) Given the allelic frequencies calculated above, what are the expected number of scaled, feathered, and horned dinosaurs in a population of the same size (218) under Hardy Weinberg Equilibrium? Show your work. (1.5 pt)

(iv) Use a chi-square test to examine whether the gene you are studying is under Hardy Weinberg Equilibrium in this population. Show your work. Do you accept or reject the null hypothesis? (2 pts)

01:119:100 Lecture Notes - Lecture 24: Mendelian Inheritance, Punnett Square, Dihybrid Cross

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