Classical Genetics

Ms.Tanyaratana Dumkua Biology Department, MahidolWittayanusorn School

https://scratchcradle.files.wordpress.com/2012/07/inheritance2.jpg

Crossing over

Gametes

Genetic inheritance

https://apbio2-chs-09.wikispaces.com/file/view/genes.gif/83602113/315x289/genes.gif https://ka-perseus-images.s3.amazonaws.com/a52d3db827139d38b820449e76ae9358f24b404a.png

http://i2.wp.com/thingsitellmymom.com/wp-content/uploads/2015/03/allele.jpg

ALLELES : gene + location

Chromosome from Dad

Chromosome from Mom

Phenotype A and B are polymorphisms of a gene expression

Phenotype, Genotype, Dominant trait, Recessive trait, Homozygous, Heterozygous

Chromosome 1 @ metaphase I

Allele of phenotype cleft chin

Allele of phenotype

no cleft

CC cc

c c C C

Heterozygous; Cc Homologous chromosome

https://cdn.education.com/files/static/science-fair/biology_it-takes/punnett-square-traits-diagram.png

Mendelian inheritance

https://cdn-images-1.medium.com/max/1200/1*Jxt7B98CJhEXDTnNI5zRTw.jpeg

Gregor Johann Mendel

https://upload.wikimedia.org/wikipedia/commons/2/2e/Mendels_peas.png

Pea

https://cdn.dtbrownseeds.co.uk/product-images/op/z/10150z.jpg

Short life Apparent characters

https://ka-perseus-images.s3.amazonaws.com/1d332b8f35d27ca033bd25ed9aa1f7470344cd80.png

Crossing fertilization

Homozygous (purple) x Homozygous (white)

Heterozygous (?)

https://dr282zn36sxxg.cloudfront.net/datastreams/f-d%3A6354a47b29926c7610584b8fa9bfc69cebaef63334cc5c62eea286a8%2BIMAGE_THUMB_POSTCARD_ TINY%2BIMAGE_THUMB_POSTCARD_TINY.1

Why?

F&P

https://sholtoainslie.files.wordpress.com/2011/09/mendel.jpg

Which is dominant trait?

Which is recessive trait?

Why does any ratio closely with 3:1?

http://s3-ap-southeast-1.amazonaws.com/subscriber.images/biology/2016/09/29120616/Monohybrid-cross-F1-generation.png https://s3-ap-southeast-1.amazonaws.com/subscriber.images/biology/2016/09/29120634/Monohybrid-cross-F2-generation.png

Monohybrid cross

Law of segregation

Only one “P” from purple parent was send to F1 generation. As same as, only one “p” from white parent was send to F1 generation.

https://i.ytimg.com/vi/yZQBdamZ3Pc/maxresdefault.jpg

From Dad From Mom

My cells

My gametes

Test cross

https://online.science.psu.edu/sites/default/files/biol011/Fig-6-8-Testcross-Outcomes.jpg

Homozygous recessive

Back cross

Parent

http://www.cas.miamioh.edu/~wilsonkg/old/gene2005/images/backcross.jpg

Dihybrid cross

http://ib.bioninja.com.au/_Media/dihybrid-cross-2_med.jpeg

Law of independent assortment Genes (alleles) on different chromosomes could be move to the same gamete.

https://cdn.thinglink.me/api/image/896466991580184578/1240/10/scaletowidth

Law of independent assortment

https://qph.ec.quoracdn.net/main-qimg-1d5ec24bae0d8099abe1c9867f577a14-c

Probability in Genetics

How many gamete types of AA in female and Aa in male?

When AA x Aa, how many type of offspring?

A

A

A

a

a

Probability to get Aa =?

How many gamete types of Aa?

When Aa x Aa, how many type of offspring?

A

Probability to get Aa =?

a

How many gamete types of AaBb?

When AaBb x AaBb, how many type of offspring?

A

Probability to get AaBb =?

a

B

B

A

a

b

b

How many gamete type of Aa?

How many gamete type of AaBb?

How many gamete type of AaBbCc?

How many gamete type of AaBbCcDd?

How many offspring genotype of Aa x Aa?

How many offspring genotype of AaBb x AaBb?

How many offspring genotype of AaBbCc x AaBbCc?

How many offspring genotype of AaBbCcDd x AaBbCcDd?

How many offspring phenotype of Aa x Aa?

How many offspring phenotype of AaBb x AaBb?

How many offspring phenotype of AaBbCc x AaBbCc?

How many offspring phenotype of AaBbCcDd x AaBbCcDd?

What is a phenotype ratio of Aa x Aa?

What is a phenotype ratio of AaBb x AaBb?

What is a phenotype ratio of AaBbCc x AaBbCc?

What is a phenotype ratio of AaBbCcDd x AaBbCcDd?

https://online.science.psu.edu/sites/default/files/bisc002/PunnettSquare.jpg

Monohybrid Dihybrid

Punnett square

AaBb x AaBb

Bb x Bb

https://i0.wp.com/www.rtgmin.org/wp-content/uploads/2012/06/punnet-square.jpg

AA x aa

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTQGEMQ2jbBA6Wdu8ojuSBtrJECIEnhggPUC4nzo-OPmmEqRMbI

Branch diagram

https://upload.wikimedia.org/wikipedia/commons/thumb/7/7d/Dihybrid_Cross_Tree_Method.png/450px-Dihybrid_Cross_Tree_Method.png

What is a probability of AABbcc after cross AaBbCc and AABBcc?