GENETICS PRACTICE Kelly Riedell Brookings Biology Watch videos BOZEMAN- Beginner’s Guide to Punnett Squares BOZEMAN- Mendelian genetics Chromosomal Genetics (Non-Mendelian) BOZEMAN- Advanced genetics

GENETICS PRACTICE PROBLEMS P1 = Parental F1 = Filial (pffspring) F2 = Filial (pffspring) http://hus.yksd.com/distanceedcourses/YKSDbiology/lessons/FourthQuarter/Chapter11/11-1/images/MendelExperiment.gif

Refresh your “Bio Brain” about: GENETICS VOCAB DOMINANT: RECESSIVE: gene that hides another represented by capital letter gene that is hidden by another represented by lower case letter

Refresh your “Bio Brain” about: GENETICS VOCAB HOMOZYGOUS (pure-breeding): HETEROZYGOUS (hybrid): Organism with two identical alleles for a gene TT OR tt Organism with two different alleles for a gene Tt

Refresh your “Bio Brain” about: GENETICS VOCAB GENOTYPE: PHENOTYPE: Genetic make up of an organism “What genes it has” Appearance of an organism “Way it looks”

Probability is the likelihood that an event will occur It can be written as a: Fraction ____ Percent ____ Ratio ____ 1/4 25% 1:3

COIN FLIP 1/2 50% 1:1 There are 2 possible outcomes: HEADS TAILS http://www.arborsci.com/CoolStuff/CoinFlip.jpg COIN FLIP There are 2 possible outcomes: HEADS TAILS The chance the coin will land on either one is: ____ ____ ____ Alleles segregate randomly just like a coin flip. . . So can use probability to predict outcomes of genetic crosses. 1/2 50% 1:1 NOT 1:2!

What is the probability? AaBBCcDd parent genome What is the probability of producing a gamete with this gene combination? ABCD ______________________________ abcD _______________________________ Abcd _______________________________

What is the probability? AaBBCcDd parent genome What is the probability of producing a gamete with this gene combination? ABCD _____________________________ abcD _______________________________ ABcd _______________________________ ½ X 1 X ½ X ½ = 1/8 ½ X 0 X ½ X ½ = 0 ½ X 1 X ½ X ½ = 1/8

What is the probability? AaBbCcDd parent genome What is the probability of producing a gamete with this gene combination? ABcd _____________________________ AbcD_______________________________ ½ X ½ X ½ X ½ = 1/16 ½ X ½ X ½ X ½ = 1/16

What is the probability? AaBbCcDd X AaBbCcDd parents What is the probability of producing an offspring with this gene combination? aabbccDd _____________________________ AaBBccDD______________________________ AaBBCCDd______________________________

What is the probability? AaBbCcDd X AaBbCcDd parents What is the probability of producing a offspring with this gene combination? aabbccDd ___________________________ AaBBccDD______________________________ AaBBCCDd______________________________ ¼ X ¼ X ¼ X ½ = 1/128 X ¼ ½ X ¼ X ¼ = 1/128 ½ X ¼ = 1/64 X ¼ X ½

What is the probability? AaBbCcDd X AaBbCcDd parents What is the probability of producing a offspring with this gene combination? AABbCcDd _____________________________ AaBbCcDd_______________________________

What is the probability? AaBbCcDd X AaBbCcDd parents What is the probability of producing a offspring with this gene combination? AABbCcDd _____________________________ AaBbCcDd_______________________________ ¼ X ½ X ½ X ½ = 1/32 ½ X ½ X ½ X ½ =1/16

PEDIGREES = male; doesn’t show trait = female; doesn’t show trait = shows trait = carrier; doesn’t show trait

1 2 3 4 Circle all males that show the trait BLUE Circle all females that show the trait RED Circle all carrier females GREEN Circle all carrier males PURPLE If this is an autosomal recessive trait, what is the genotype of individual #1? If this is an autosomal recessive trait, what is the genotype of individual # 2? If this is an autosomal recessive trait, what is the genotype of individual #3?

1 2 4 3 Circle all males that show the trait BLUE Circle all females that show the trait RED Circle all carrier females GREEN Circle all carrier males PURPLE If this is an autosomal recessive trait, what is the genotype of individual #1? If this is an autosomal recessive trait, what is the genotype of individual # 2? If this is an autosomal recessive trait, what is the genotype of individual #3?

Write the genotype of each individual next to the symbol. Is it possible that this pedigree is for an autosomal recessive trait?  

Write the genotype of each individual next to the symbol. Aa Aa Aa or AA aa Is it possible that this pedigree is for an autosomal recessive trait?   YES

Write the genotype of each individual next to the symbol. Is it possible that this pedigree is for an X-linked recessive trait?  

Write the genotype of each individual next to the symbol. XB Y XB Xb XB Y Xb Xb  Is it possible that this pedigree is for an X-linked recessive trait? NO

Could this trait be inherited as AUTOSOMAL RECESSIVE? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Fill in genotypes of affected individuals Is this trait inherited as AUTOSOMAL RECESSIVE?   Fill in genotypes of affected individuals aa aa aa aa aa aa aa aa aa http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Yes Possible if . . . Is this trait inherited as AUTOSOMAL RECESSIVE? aa Aa A ? aa aa aa aa aa aa aa aa http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Is this trait inherited as AUTOSOMAL DOMINANT? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Fill in genotypes of affected individuals Is this trait inherited as AUTOSOMAL DOMINANT?   Fill in genotypes of affected individuals A ? A ? A ? A ? A ? A ? A ? A ? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

NO If individual shows trait one of parents must also have trait. Is this trait inherited as AUTOSOMAL DOMINANT?   NO If individual shows trait one of parents must also have trait. A ? A ? A ? A ? A ? A ? A ? A ? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Is this trait inherited as X-LINKED RECESSIVE? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Fill in genotypes of affected individuals Is this trait inherited as X-LINKED RECESSIVE?   Fill in genotypes of affected individuals XaXa XaY Xa Y XaXa XaY XaY XaXa XaY XaXa http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

NO If female has trait dad must show it too Is this trait inherited as X-LINKED RECESSIVE?   NO If female has trait dad must show it too XAXa XA Y XaXa XaY XaY Xa Y XaXa Daughter has trait, but dad doesn’t have allele or would be filled in XaY XaXa XaY XaXa http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Is this trait inherited as X-LINKED DOMINANT? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

Fill in genotypes of affected individuals Is this trait inherited as X-LINKED DOMINANT?   Fill in genotypes of affected individuals XAX? XAY XA Y XAX? XAY XAY XAX? XAY XAX? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

NO If male has it came from mother If dad has it, so should daughters Is this trait inherited as X-LINKED DOMINANT?   NO If male has it came from mother If dad has it, so should daughters XAX? XAY Dad has it but not daughters XAY XA Y XAX? XAY XAX? XAY Son has it, but mom doesn’t XAX? http://www.mansfield.ohio-state.edu/~sabedon/biol1128.htm#A1

If dad passed to son it must be AUTOSOMAL The inheritance of the disorder in II-3 from his father rules out what form of inheritance? Xb Y Can’t be X-linked recessive Males get their X-linked allele from their mother If dad passed to son it must be AUTOSOMAL Xb Y http://www.mybookezzz.org/ebook.php?u=aHR0cDovL21jYi5iZXJrZWxleS5lZHUvY291cnNlcy9tY2I0MS9wcmFjdGljZV9wcm9ibGVtc19hbnN3LnBkZgpQcmFjdGljZSBwcm9ibGVtcyAod2l0aCBhbnN3ZXJzKSBUaGlzIGlzIHRoZSBkZWdyZWUgb2YgZGlmZmljdWx0eSBvZiAuLi4=

If CLOSE TOGETHER on homologous chromosomes, STAY TOGETHER and end up together 100% of time Act like one gene

http://image. slidesharecdn http://image.slidesharecdn.com/meiosisnotes-100204185918-phpapp02/95/meiosis-notes-23-728.jpg?cb=1265310007 CROSSING OVER If far apart on homologous chromosomes, end up together 50% of time RECOMBINANTS- Put different maternal/paternal alleles together on different chromosomes

INDEPENDENT ASSORTMENT http://image.slidesharecdn.com/meiosisnotes-100204185918-phpapp02/95/meiosis-notes-23-728.jpg?cb=1265310007 INDEPENDENT ASSORTMENT If on different chromosomes, END UP TOGETHER 50% of time.

A Wild type fruit fly (heterozygous for gray body and normal wings) is mated with a black fly with vestigial wings. OFFSPRING: 778- wild type 785- black-vestigial 158- black- normal wings 162- gray body-vestigial wings Is it 9:3:3:1? (2 genes on 2 different chromosomes) Is it 3 Wild type : 1 black vestigial? (linked on homologous chromosomes)

A Wild type fruit fly (heterozygous for gray body and normal wings) is mated with a black fly with vestigial wings. OFFSPRING: 778- wild type 785- black-vestigial 158- black- normal wings 162- gray body-vestigial wings What is the recombination frequency between these genes?

A Wild type fruit fly (heterozygous for gray body and normal wings) is mated with a black fly with vestigial wings. OFFSPRING: 778- wild type 785- black-vestigial 158- black- normal wings 162- gray body-vestigial wings Recombinants = Total 320 = 17% 1883

When F1’s make gametes PROPHASE I Crossing over makes recombinants Wild type wings Wild type body (yellow-brown) Vestigial wings Black body Parents (P) F1 offspring When F1’s make gametes PROPHASE I Crossing over makes recombinants CROSS WITH HOMOZYGOUS RECESSIVE

A Wild type fruit fly (heterozygous for gray body and normal wings) is mated with a black fly with vestigial wings. OFFSPRING: 778- wild type 785- black-vestigial 158- black- normal wings 162- gray body-vestigial wings What is the recombination frequency between these genes?

A Wild type fruit fly (heterozygous for gray body and normal wings) is mated with a black fly with vestigial wings. OFFSPRING: 778- wild type 785- black-vestigial 158- black- normal wings 162- gray body-vestigial wings What is the recombination frequency between these genes? Recombinants = Total 314 = 16.7% 1877

A Wild type fruit fly (heterozygous for gray body and red eyes) is mated with a black fly with purple eyes. OFFSPRING: 721- gray body/red eyes 751- black body/purple eyes 49- gray body/purple eyes 45- black body/red-eyes What is the recombination frequency between these genes?

A Wild type fruit fly (heterozygous for gray body and red eyes) is mated with a black fly with purple eyes. OFFSPRING: 721- gray body/red eyes 751- black body/purple eyes 49- gray body/purple eyes 45- black body/red-eyes What is the recombination frequency between these genes? Recombinants = Total 94 = 6 % 1566

A Wild type fruit fly (heterozygous for normal bristles and red eyes) is mated with a spineless bristle fly with sepia eyes. OFFSPRING: 648- normal bristles/red eyes 681- spineless bristles/sepia eyes 72- normal bristles/sepia eyes 83- spineless bristles/red-eyes What is the recombination frequency between these genes?

A Wild type fruit fly (heterozygous for normal bristles and red eyes) is mated with a spineless bristle fly with sepia eyes. OFFSPRING: 648- normal bristles/red eyes 681- spineless bristles/sepia eyes 72- normal bristles/sepia eyes 83- spineless bristles/red-eyes What is the recombination frequency between these genes? Recombinants = Total 155 = 10.4% 1484

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-D 10% B-C 15% B-D 5%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-D 10% B-C 15% B-D 5%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-D 30% B-C 24% B-D 16%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-D 30% B-C 24% B-D 16%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-D 30% B-C 24% B-D 16%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-D 30% B-C 24% B-D 16% CABD

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-B 8% A-C 28% A-D 25% B-C 20% B-D 33%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-B 8% A-C 28% A-D 25% B-C 20% B-D 33%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-B 8% A-C 28% A-D 25% B-C 20% B-D 33%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-B 8% A-C 28% A-D 25% B-C 20% B-D 33%

Determine the sequence of genes along a chromosome based on the following recombination frequencies A-B 8% A-C 28% A-D 25% B-C 20% B-D 33%

A large ear of corn has a total of 500 kernals, including 312 purple & starchy, 73 purple & sweet, 76 yellow & starchy, and 39 yellow & sweet. HYPOTHESIS: This ear of corn was produced by a dihybrid cross (PpSs X PpSs) involving two pairs of heterozygous genes resulting in a theoretical (expected) ratio of 9:3:3:1. Test your hypothesis using Chi-square and probability values. SHOW YOUR WORK!

TOTAL = 500 offspring IF 9:3:3:1 then expect: H0- There is no difference between the frequencies observed and the frequencies expected for a HETEROZYGOUS DIHYBRID (9:3:3:1) cross. TOTAL = 500 offspring IF 9:3:3:1 then expect: Purple & Starchy = 500 X 9/16 = 281.25 Purple & Sweet = 500 X 3/16 = 93.75 Yellow & Starchy = 500 X 3/16 = 93.75 Yellow & Sweet = 500 X 1/16 = 31.25 312 73 76 39 281.25 93.75 31.25 30.75 -20.75 -17.75 7.75 945.56 430.56 315.06 60.06 3.36 4.59 1.92 13.23 4-1= 3 13.23 is larger than 7.82 REJECT THE NULL There is a difference between observed and expected for 9:3:3:1 = NOT A 9:3:3:1 cross