Linkageeee Flashcards by Samrudhi Menthe

Link gene
Linkage , exception of
First time observed by
Experiment and () by

All the gene present in one / same chromosome
The phenomenon of collective inheritance of character / gene ( link , mendacity law of independent assortment
Bateson and Punnett ( coupling and repulsion theory )
Term , Morgan ( drosophila Melanogaster ) ( fruit fly

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Drosophila melanogaster reasons 1 , life span
Many _____ ______ character which have
Male () , female () , chromosome no
Autosome + sex chromosomes

Can be easily grown in synthetic media / laboratory , 2 weeks
Observable , contrasting , variation
Short , long , 8
3 pair + 1 pair ( human like

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Break the linkage , can
Occur b/w
Link gene are always
Are +nt

Crossing over / recombination , can separate the link gene
Non sister chromatid of chromosome in Pachytene
Non allelic
+ nt on same chromosome

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Linkage ____ proportional to 1
2
1and2
Factors affecting crossing over 1
2
3
4 sex gender co absent in

Indirectly crossing over
Distance
C.O directly proportional to distance
Distance , increase co increase
Temp increases co decrease
Age increase co decrease
Male drosophila , in female silkworm

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Complete linkage ,co is (%) co , linkage , new combination
Eg
Behave like , geno pheno

Absent , 0%,100%,0%
Few genes of male drosophila , female silkworm
Mono hybrid cross , 1:2:1 ,3:1

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Incomplete linkage most , parental combo ___ new combo
Max frequency of recombination
Arrangement of linked gene on chromosome
A
B occur due to

Common type of linkage&raquo_space;>
50%
CIS Arrangement/ coupling = original arrangement/ pour
Trans arrangement / repulsion = mutation

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Genetic map //

Distance _____ proportional to
1% recombinated =

Linkage map , chromosomal map
Is a straight line in which different gene are linearly arranged in specific sequences separated by distance
Directly crossing over
1 cM ( centiMorgan ) or 1 mu ( map unit distance

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Recombination frequency/
Who prepared first chromosomal map of drosophila , by using
Uses

Cross over value = no of recombinant offspring / total no of offspring x100
Alfred sturtevant = recombination frequency
Distance b/w two linked gene
Sequence of linked gene

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In drosophila
Character Trait / wild. Trait mutant (recessive
Eye colour
Body colour
Wing shape
Gene of are character are located in

Red eye W+ White eye W
Brown colour Y+. Yellow colour Y
Normal wings M+. Miniature M
X chromosome

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Cross A body colour and eye colour f2 gen parental ( linkage %), recombinant
Cross B eye colour and wing size
Autosome chromosome, sex chromosomes/

Case A = 98.7%, 1.3%
Case B = 62.8%,37.2 %
44 , Allosome XX/ XY

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X linkage = ,eg
Y linkage() = , eg

Both male and female , haemophilia , colourblindness
Holandric character- only in male ,
Sry gene (TDF = testis determining factor
Hypertrichosis
Purcupine skin
Webbed toe

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Haemophilia //=
Alleles

Blood clotting time normal human

Bleeding , royal disease = sex linked recessive disease
44+XY = normal male , 44+XX = normal female , 44+XḥY = haemophilic male
44+XXḥ = normal / carrier female , 44+XḥXḥ = lethal gene ( die in embryonal stage )
1-8 min
30 min to 24 hour

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Bleeding types
1
2
3
In this disease a single

Haemo A = blood clotting factor 8 absent ( royal disease 8= antihaemophilic globulin ahg
Haemo B = B.c.f 9 absent ( Christmas factor = plasma thromboplastin component
Haemo c = B.c.f 11 absent
Protein that is part of cascade of protein involved in clotting of blood affected

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Haemophilic son how
Female
Types of colour blindness
Test

By heterozygous female / carrier
Extremely rare mother = carrier, father = diseased ( die due to leathal gene
Protonopia = red , deuteronopia = green , tritonopia = blue
Ishihare chart

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Colour blindness is not , more common in (reason
Male %, female %
What results in failure to distinguish b/w green , blue,red
Due to
Daughter will be colourblind

A leathal disease , male , due to hemizygous condition
8%,0.4%
Either red or green cone eye defected
Mutation in certain gene present in X chromosome
Mother = carrier , diseased , father diseased

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Types of inheritance of sex link character
A) ____/___. eg 1/
2) = /
If gene +nt in
B) =1 /
2=/
If gene +nt in

A) criss cross inheritance/ Morgan = grandfather then mother than son = diagenic
2 grandmother than son than grand daughter = dia andric
X chromosome
B) Non criss cross inheritance = g. father then father than g son = Holandric
2 ) g mother than daughter than g daughter = hologenic
Y chromosome

Sex limited character , +nt in
Expression of gene controlled by
eg , gene located on
Eg

One sex ( gender ) and absent in another sex but there genes are +nt in both
Sex hormones
secondary sexual characters , Autosome
Gene of beard and mustache ( control by testosterone hormones )

Sex influenced character, gene of these character +nt
_____ +nt in male in __… condition , inf female
Geno male , female BB , bb Bb
Male honey bee quote

On Autosome but their expression different in male and female
Baldness in heterozygous, absent
+nt both , absent both , male +nt female absent
I have no father and no son but I have grandfather and grandson

Mechanism of sex determination types a)1
2
B)
X chromosome name given by ,year

Allosomic determination of sex 1) XX-XY or lygaeous eg human
2) XX female and Xo male / protenor type eg insects grass hopper , cockroach
Haploid - diploid mechanism sex determination on bee
Henking in 1891 observed a structure in some sperm of insect

Homo genetic parent = , produce eg
Heter= ,produce decide eg
Allosomic determination of sex regulate
1 ) XX-XY / first seen by ,in
Types 1
Eg

Both sex chromo similar and produce 1 type of gamete eg human female
Both sex chromo dissimilar and produce 2 type of gamete , human male
Somatic characters
Lygaeus type by Wilson and Steven’s in lygaeus insect
XX female ( homo Gametic and XY male ( hetero
Human , drosophila , mammals

Allosomic
Lygaeus type second example = female,male
Eg
XX female and XO male / = female , male ()
Eg

ZW female and ZZ male = female hetero (2 gamete ) male homo
Birds , moth , fish , butterfly , reptile
Protenor = F = homo , M = hetero
Most of insect grass hopper(23) , cockroach

Hhjj

Haploid - diploid mechanism / , sex deter occurs on basis of
Female , male chromo
Male () develops from ,by
Females (,) = ===

Sex determination in honey bee , number of sets of chromosomes
Diploid ( two sets of chromo) 32, haploid ( one set of chromo 16
Drone from unfertilised eggs by parthenogenesis
Queen and worker bee female from diploid eggs I.e fertilised

Drone produce sperm by, queen worker difference
Human genetics
Eugenics =
Father

Mitosis , q= feeds on royal jelly , w= bee bread
Study or analysis of genetic characters in human
Improvement of human beings by applying principles of genetics
Francis Galton

Genetic disorder main two types A) types1, eg Type 2 eg 1

A) Mendelian disorder B ) chromosomal disorder Autosomal = dominant- myotonic dystrophy, recess = sickle cell anemia , thalessemia , phenylketonuria, alkaptonuria , albinism , cystic fibrosis Sex linked X linked domi - pseudorickets , rece - colour blindness, Haemo , DMD = duchenne muscular dystrophy Y linked sry , TDF

Mendelian disorders determined by Most common disorders ,,,,,, Environmental mechanism eg 1

Alterations or mutation in single gene Haemophilia, cystic fibrosis, SCA , colour blindness, phenylketonuria, thalassemia In Medusa fish , turtles cool temp = male , hot temp = female In crocodile cool = female , hot = male

Genetic balance theory g.i Mutation type 1 types and eg

Genetic index = no of X chromosome/ set of chromosomes Quantity( genomatic mutation ) / quality chromosomal abbreviation Aneuploidy ( only few no of chromosome alter ) Monosomic eg turner syndrome n-1 Nullisomic n-2 Trisomic n+1 Tetrasomic n+2

Genomic mutation second type Eg Quality / eg,,,,,

Polyploidy set of chromosomes alter Haploid , triploid , tetraploid Chromosomal abbreviation Deletion (end portion delete ), interstial ( mid portion delete ), duplication ( copy Translocation ( certain part change location ) , inversion ( ulata

Mutation , it’ is a Down syndrome first discovered by , year Genetic disorder caused by ( mono / null / tri ), total chromosome

Sudden change in quality or quantity of genetic material which cause change in geno phenotype , discontinuous change and inheritable Langdon Down , 1866 Presence of 1 additional copy of chromosome no 21 ( tri ) , 47

Symptom of down syndrome Height Head , tongue Mouth , ,,,, Retarded Disease Tips

Short statured Small round head Furrowed tongue ( big and wrinkled Partially open mouth Palm crease ( broader Physical , pyshomator and mental development is retarded Congenital heart disease Many loops on finger tips

Klinefelter’s syndrome also a genetic disorder caused by ,in , geno total chromosome Overall development , also development eg , such individual are Turner syndrome occur due to , geno total chromosome Eg of ( mono / null / tri ), such ~____ are

Additional X chromosome in male human , 44+XXY, 47 Musculine , feminine gynaecomastia = breast development , sterile , tall Absence of one X chromosome 45 ( 44+XO Mono , female are sterile

Turner syndrome symptoms Mutagens Eg 1,,, used to reduce mutation 2 3

Short statured and undeveloped feminine chara , poor breast development, Rudimentary undeveloped ovary , no menstrual cycle , lack of sec sex chara Agents which cause mutation Physical uv rays ttdimer ( thymine thymine dimer ) , x ray , gamma ray , used in plants Chemical NMU , dye , chalchicine , mustard gene Biological Viruses

Sickle cell anemia blood =, = ,=,= Right , mutation amino acid , rna dna Associated with This disease caused due to Under

RBC, Hb ,beta protein , 6 th amino acids Glutamic acid , valine , GAG , GUG , GAG - CTC , GTC - CAC Leathal gene , codominance , Pleiotropic( disease cause , resistance power malaria , organ development) ,point mutation Mutation of gene controlling beta chain of hb, Low o2 tension , Hb polymerisation

Phenylketonuria caused due to , in born error of , also inherited as , cause / lack of ( convert As a result Cause

Mutation in gene that codes for enzyme phenyl alanine hydrolyse ( single gene muta Metabolism , autosomal recessive Liver enzyme named phenyl alanine hydroxyliase enzyme,phenyl alanine Aa intotyrosin Phenyl alanine accumulates and converts into phenyl pyruvic acid phenyl pyruvic acid accumulation cause mental retardation

Phenylalanine excreted through ,ex of Also caus e Thalassemia is also an , when both the parents are Due to either ()

Urine because of its poor absorption of kidney , single gene mutation Reduction in hair ,skin pigmentation Autosomal linked recessive blood disease , unaffected carrier of the gene ( hetero Mutation or deletion( alpha beta chain absence or reduced

Thalassemia free globulin ,,,,( characteristic of this disease Types 1, two gene namely means ,on chromo no of , Excess of ( adult, new born baby Excess of beta chain form , concerned with deletion of

Chain accumulates inside RBC and damage the cell causing cellysis result in anemia Alpha = HBA1, HBA2 4 allele , 16 each parent Beta chain in adult (alpha 2,beta 2) or gamma in new born baby ( alpha 2 gamma 2 Unstable Tetramer , 16 p (short arm

Beta thalassemia involve gene no ____ , chromo no , occurs during to mutation of Excess formation Delta thalassemia % Thalassemia originated in

1 HBB ,11, 1 or both the gene Of alpha chain which bind with RBC mem ( anemia ) and damage it About 3 % adult have alpha and delta Meditaerian region

Difference b/w sca and thalassemia

SCA = qualitative problem synthesising an incorrectly functioning globulin Thalassemia = quantitative problem synthesising too few globin molecules