Chapter 1 Introduction to the Study of Genetics (1)

8/17/2019 Chapter 1 Introduction to the Study of Genetics (1)

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Introduction to

Genetics

© 2015 PearsonEducation, Inc.

the branch of biology concernedwith the study of heredity and

variation

ha!ter 1


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"istory of Genetics


1#00$1%50& 'he (awn of )odern *iology

+illia "arvey& Theory of epigenesis• -tructures such as body organs

• are not initially !resent in the early ebryo• are fored later

1%0& -chleiden and -chwann& The cell theory• /ll organiss are co!osed of basic

structuralunits called cells


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'he rigin of -!ecies


• 1%5& (arwin !ublished his ideas on thetheory of evolution in The Origin of Species

• Descent with modification• Eisting s!ecies arose fro other ancestral s!ecies

• Natural selection• 'he echanis for evolutionary change

• Theory of evolution•

Inde!endently !ro!osed by /lfred 3ussel +allace


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• 1%##& )endel !ublishes his findings


•

)endel wor4ed with !eas and useduantitative data to su!!ort his ideas• 'raits are !assed fro generation to

generation

•

'ransission of genetic inforation fro!arents to offs!ring


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)itosis and )eiosis


• Mitosis• hroosoes are co!ied and distributed• 'he two resulting daughter cells each receive a

diploid set

• Meiosis•

hroosoes are co!ied and distributed• 3esulting cells 6gaetes7 receive a ha!loid set

of chroosoes


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hroosoal 'heory

of Inheritance


• Inherited traits are controlled by genesresiding on chroosoes

• Genes are transitted through gaetes• )aintains genetic continuity fro generation to

generation


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Genetic 8ariation


• Alleles• )utations !roduce alleles of a gene• 'he source of genetic variation

• Genotype• 'he set of alleles for a given trait

• Phenotype• E!ression of the genoty!e• Produces an observable trait or !henoty!e


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(9/ Is the arrier of

Genetic Inforation


• (9/ is the carrier of genetic inforation• 9ot !rotein• 3esearch of /very, )ac:eod, and )carty

• In 1;;, !ublished e!erients showing (9/ wascarrier of genetic inforation in bacteria


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© 2015 PearsonEducation, Inc. Figure 1-7


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-tructure of (9/


• (9/ is• anti!arallel• double


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-tructure of 39/


• 39/ is siilar to (9/, ece!t that• it is usually single


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'he entral (ogaof )olecular

Genetics

•

(9/ is transcribed to39/

• 39/ is translated into

!rotein



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'he Genetic ode


• #odons• 'ri!let nucleotides !resent in 39/• 'he genetic code

• Each tri!let encodes for insertion of as!ecific aino acid into a growing !rotein

chain


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Proteins


• Proteins are the end !roduct of genee!ression

• Protein action or location in a cell !roduces!henoty!e6s7

•

(iversity of !roteins• 20 different aino acids• 9uerous cobinations of these 20


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3ecobinant (9/ 'echnology



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3estriction En>yes


• 1?0s& researchers discovered thatrestriction en>yes in bacteria cut viral(9/ at s!ecific sites

• 3estriction en>yes allowed the advent ofrecobinant (9/ and cloning


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*iotechnology


• *iotechnology is now used in• health care• su!erar4et !roducts

• agriculture• court syste


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*iotechnology =sed in

/griculture


• *iotechnology has been used for the genetic

odification of cro! !lants for• increased herbicide, insect, and viral resistance• nutritional enhanceent• water use reduction


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*iotechnology in Genetics

and )edicine


• *iotechnologyed in !renatal diagnosis• 'ests for heritable disorders


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Genoics, Proteoics, and

*ioinforatics


• Genomics• -tudies the structure, function, and evolution of

genes and genoes

• Proteomics• Identifies a set of !roteins !resent in cells

under a given set of conditions• -tudies their functions and interactions

• $ioinformatics• =ses hardware and software for !rocessing

nucleotide and !rotein data


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oon rigin


• /ll life has a coon origin

•

Genes with siilar functions in differentorganiss are siilar in structure and in(9/ seuence


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)odern /!!roaches to

=nderstanding Gene @unction


• %everse genetics• (9/ seuence of a !articular gene of interest6GI7 is 4nown, but its function is not

• Gene &noc&out• /llows scientists to render genes nonfunctional

to investigate the !ossible role of that gene


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)odel rganiss =sed to

-tudy "uan (iseases


• )odel organiss for genetic study eetthese criteria&

• Easy to grow• -hort life cycle• Produce any offs!ring• Genetic analysis is straightforward


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)odel rganis& "istorical

and )odern• @irst generation of odel organiss&

son© 2015 PearEducation, Inc. Figure 1-13


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)odel rganis& "istorical

and )odern


• )odern odel organiss&• 8iruses& ' !hages and labda !hages• *acteria& Escherichia coli

• Aeast& -accharo,yces cerevisiae


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'he /ge of Genetics


• 1%#5& )endel set the stage for the study ofgenetics

• Genetics ra!idly develo!ed fro )endelBs!eas to the "uan Genoe ProCect

• 1#2& 9obel Pri>e awarded to +atson, ric4,and +il4ins• 9uerous 9obel Pri>es have been awarded since

then in the field of genetics

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Chapter 1 Introduction to the Study of Genetics (1)