Genetics Flashcards
(132 cards)
1
Q
Term genetics was coined by
A
Bateson.
2
Q
Father of genetics is
A
Gregor John Mendel
3
Q
Living organism studied in classical genetics is/was
A
Pea plant (pisum sativum) = garden pea Mendel also tried to work on Hawk-weed (Hieraceum).
4
Q
Which technique is used in classical genetics
A
Hybridization
5
Q
Father of modern genetics is
A
Bateson
6
Q
Father of experimental genetics is
A
T.H.Morgan
Aka flyman of genetics (bcz he worked on fruitfly)
7
Q
Living organism studied in modern genetics was/is
A
Fruitfly ( Drosophila melanogoster) and Pink bread mould (Neurospora crassa) aka drosophila of plant kingdom.
8
Q
Father of human genetics is
A
Sir Archibald Garald.
Worked on a genetic disorder c/d Alkaptoneuria.
9
Q
Drosophila of plant kingdom is
A
Pink bread mould (Neurospora crassa).
10
Q
What’s Eugenics?
A
Improvement in human race by application of genetics.
11
Q
Whats euphenics?
A
Application of genetics for treatment of genetic disorders.
12
Q
Whats euthenics?
A
Improvement in human race by providing proper environment.
13
Q
Diagynic inheritance?
A
Transmission of charac. from male to male “via female”.
Dia=via ; gynae=female
14
Q
Diandric inheritance?
A
Transmission of charac. from female to female “via male”.
Dia=via ; andric =male
15
Q
Holoandric inheritance?
A
Transmission of charac from male to male to male and so on.
Holo=complete ; andric =male
16
Q
Hologynic inheritance?
A
Transmission of charac from female to female to female and so on.
Holo = complete ; gyna =female
17
Q
Name the modes of transmission (found in majority).
A
Diagynic
Diandric
Hologynic
Holoandric
18
Q
Physical basis of heridity is
A
Gene
19
Q
Chemical basis of heredity is
A
DNA 🧬
20
Q
_________ is the basis of heredity. [ncert]
A
Inheritance
21
Q
Who first time applied statistical analysis & mathematical logic to problems in biology?
A
Mendel.
During his investigations into inheritance patterns…
22
Q
Pre-formation theory was given by
A
Swammerdam
Found small humans inside head of sperms and c/d them homunculus.
23
Q
Theory of pangenesis was given by
A
Darwin.
24
Q
Theory of continuity of germplasm was given by
A
Weisman.
Said: somatoplasm isn’t inherited (mortal) whereas germ plasm is inherited (immortal).
25
Sutton & boveri gave ______ theory regarding heredity.
Chromosomal theory of inheritance.
26
Discontinuous variations (org. is deviated from normal) occur due to
Exposure to some mutagens (x-rays, gamma rays, uv rays, silver nitrate, benzopyrene etc)
27
Continuous variation (org. isn’t deviated from normal) occur due to
Crossing over.
28
D.O.B of Mendel
20th July, 1822 in Hezendorf, Austria. “(Austrian monk)”
29
Mendel cultivated plants for 7 yrs from ____to ___.
1856-63 : he cultivated 25,000 pea plants.
30
Mendel published his work/paper in
1865.
31
Death of Mendel
6th jan,1884 due to chronic nephritis (kidney failure).
32
Main reason for Mendel’s success was
Luck
33
Other reasons for Mendels success are
Luck
Hardwork
Scientific attitude
Mathematical background
34
Who re-discovered Mendels work and when?
In 1900, 3 scientists- Hugo de vries, Correns, Tschemark re-discovered Mendel’s work.
1900 => 16 yrs after his death or 34yrs after his publication
35
Name the dutch scientist who re-discovered Mendel’s work?
Hugo de vries from Holland ( dutch )
36
Correns was from Germany and Tschemark was from Austria.
| T/F
True.
37
Who re-published Mendel’s work and in which journal?
Hugo de vries re-published Mendel’s work in ‘Flora’ in 1901.
38
Term gene was coined by
Johnssen.
| Gene aka medelian factor aka factor.
39
Term allele was coined by
Bateson
40
Dominant allele is the one that expresses in
Heterozygous condition only.
41
Number of traits selected by Mendel were??
14 i.e 2x7 characters
42
```
Complete the table:(in order that chr.no. follows 4414571 )
Characters studied by Mendel | Dominant | Recessive | Chr.no.
1)
2)
3)
4)
5)
6)
7)
```
```
Hgt. Of plant _ Tall _ Dwarf _4
Flower position _Axial _Terminal _4
Flower colour _Violet _white _1
Pod shape _inflated _constricted _4
Pod colour _green _yellow _5
Seed shape _round _wrinkled _7
Seed colour _yellow _green _1
```
Note:to denote these, consider 1st letter of each dominant charac.
Egs., Violet => V => VV & vv
43
Characters studied by Mendel are present on __ chromosomes with no.s __,__,__,__.
4 chromosomes
| I.e 4,1,5,7
44
No. Of gametes formed =
2^n
Where n is the no. Of heterozygosities.
Eg., AaBbCCeeDd
Here n=3 as Aa , Bb & Dd are heterozygous where as CC & ee are homozygous.
=> no. Of gametes = 2^3=8
**on how to make these gametes, refer notebook.
45
Phenotypic ratio for mono hybrid cross is
3:1
| I.e tall:dwarf = 3:1 or round:wrinkled or dominant:recessive type
46
Genotypic ratio for mono hybrid cross is
1:2:1
| TT : Tt: tt type
47
Phenotypic ratio for di hybrid cross is
9:3:3:1
| T,R : T,r : t,R : t,r type
48
Genotypic ratio for dihybrid cross is
1:2:1:2:4:2:1:2:1
To know how this looks in punett square refer notebook
49
In general, phenotypic & genotypic ratio is given by
Phenotypic ratio = (3:1)^x where x is cross no.
Genotypic ratio = (1:2:1)^x where x is cross no.
For mono hybrid cross, cross no.=1
For dihybrid cross, x = 2 .... so on
50
1) Phenotypic & genotypic ratio remains same for reciprocal cross.
2) By exchanging parents, there’s no change in phenotypic or genotypic ratio.
Both statemnets are correct & 2 maybe regarded as correct explanation of 1.
As, cross obtained by exchanging the parents is K/a reciprocal cross.
51
Whats back-cross?
Cross of f1-generation with its parents.
Back-cross = f1 x parent
52
F1 x dominant parent =
| F1 x recessive parent =
F1 x dominant parent = out-cross
| F1 x recessive parent = test-cross
53
Mono hybrid test cross ratio =
1:1
| I.e dominant:recessive
54
Dihybrid test cross ratio =
1:1:1:1
55
Name laws of inheritance
Law of dominance. [ 1st law as per ncert]
Law of unit factors.
Law of segregation. [ 2nd law as per ncert] {@1}
Law of independent assortment. {@2}
{actually 1st law, 2nd law}
56
State Mendel’s 1st law?
Aka law of dominance.
States that :
i) Characters are controlled by discrete units cd factors/genes.
ii) Factors occur in pair.
iii) In heterozygous condition one gene dominates (dominant) the other is recessive.
57
Exceptions of law of dominance?
Multiple allelism
Incomplete dominance
Co-dominance
Differential dominance
58
Concept of incomplete dominance was given by
Correns
59
Intermediate phenotype is produced in
Incomplete dominance.
60
Examples of incomplete dominance are
Flower colour in 4 o clock plant (mirabilis )=red/pink/white
Flower colour in snap dragon = red/pink/white
Feather coat colour in case of Andulasian foul =black/blue/white
Starch synthesis in pea = large/medium/small sized
61
Whats the phenotypic & genotypic ratio in incomplete dominance?
Phenotypic as well as genotypic ratio is 1:2:1
62
Presence of more than 2 alleles for a single gene is called
Multiple allelism
63
Examples of multiple allelism are
ABO-Blood group system
| Skin coat colour in case of rabbits = agouti /chinchilla /Himalayan albino / albino
64
No. of phenotypes & genotypes ,of ABO blood group system ,respectively are
4 & 6
4= A/B/AB/O
6= iaia/ibib/iaib/ioio/ibio/iaio
65
No. Of possible combinations is
n(n+1)/2
Where n is no. Of alleles.
Used for qs like : if a gene has n alleles then no. Of combinations will be?
66
Condition in which both alleles of a gene are able to express equally in same organism is called
Co-dominance
67
Examples of co-dominance
ABO- blood group system
MN-blood group system
RS-blood group system
68
Father of blood groups is
Karl Landsteiner
He gave the concept of blood groups in 1901.
69
Whats blood group?
Concept based on presence or absence of different types of surface antigens present on the surface of RBC’s.
70
In humans __ types of blood group systems exist.
33
As reported by ISBT (international society for blood transfusion) in 2012.
71
A/B/O blood groups where discovered by ______ & AB was later discovered by ______.
Landsteiner (1901)
| de-Castello (1902)
72
```
A-blood group has:
Antigen-A
Antibody-A
Both
None
```
Has antigen-A
Produces anti-B
Can receive from A and O
73
Universal recipient/acceptor is
AB-blood group
As it has antigen-A as well as antigen-B
Produces neither anti-A nor anti-B
Can receive from A,B,AB,O
74
Most common type of blood group in world is
O
75
Rh-blood group system was discovered by
Eischer.
| He Studied RBC’s of monkeys (Rhesus)
76
9q34 represents
On chromosome 9, long arm, 34th gene
In humans, 9q34 Has 3 alleles ia / ib / io
77
In humans on chromosome 1, long arm, 35th gene i,e 1q35 has 2 alleles. Name them.
Ia / Ir.
78
IRIR or IRIr represents
Rh-positive blood group
Has antigen-Rh
doesn’t produce anti-Rh, so it can receive from Rh +ve & Rh -ve
79
Can Rh-ve blood group receive blood from Rh+ve
No.
| Bcz it produces anti-Rh.
80
Universal recipient is
AB+ve
81
Universal donor is
O-ve
82
Blood group testing is based on
agglutination reaction (clumping of cells).
83
Many gene 1 character expression is called
Polygeny.
84
________ is aka quantitative inheritance.
Polygeny.
85
Examples of polygeny are
Human skin colour
| Kernel colour in wheat
86
Skin colour is controlled by ___ gene.
3 genes (AABBCC)
Total gene = 3
Total alleles = 6
87
XX-XY method is found in
Mammals
Drosophila
Some bryophytes
88
XX-XO method is found in
Grass hoper and cockroaches
89
ZW-ZZ method is found in
Birds
Reptiles
Fishes
90
ZO-ZZ method is found in
Butterflies
| Moths
91
Haplo-diploidy is found in
Bees
Ants
Wasps
92
Sex id determined by environmental factors in
```
Turtles
Lizards
Crocodile
Alligators
Bonelia
Cripidula
American crocodile
```
93
Cytoplasmic inheritance concept was given by
Correns from 4O’ clock plant (mirabilis)
94
Whats cytoplasmic inheritance
Inheritance of plasma genes/cytoplasmic genes/extra-nuclear genes from parents to offsprings.
95
Properties of cytoplasmic inheritance are?
Shows maternal effect (more influence of mother on expres of such genes).
Reciprocal cross shows different result than normal cross. Therfore aka Non-Mendelian inheritance.
Controlled by plasma genes.
Gene mapping is difficult.
96
Chromosomal theory of ’linkage’ was given by
Morgan and Castle.
97
Postulates of chromosomal theory of linkage?
Genes present on same chromosome are termed as linked genes.
Linked genes have tendency to remain and inherit together.
Linked genes may occasionally get separated by crossing over.
Chances of separation depend upon strength of linkage.
Strength of linkage depends on distance b/w 2 genes.
98
Can linked genes be separated. If yes, then how?
Yes. Linked genes may get occasionally separated by crossing over.
99
Whats recombination frequency?
Recombinants upon tot. No. Of offsprings x 100
Its the %age of recombinants in any cross.
Recombinants = new combinations that were not present in parent.
100
Calculate the distance b/w 2 genes?
Measured indirectly using RF (recombination frequency).
Distance is said to be ‘x’ cM if RF is x%.
Unit = cM (centi-morgan)
101
10cM =
| 100cM =
```
10cM = 1dM (deci-morgan)
100cM = 1M (morgan)
```
102
Whats linkage groups ?
All genes present on one chromosome represent one linkage group.
No. Of linkages groups = haploid chromosome no.
103
No. Of linkage groups in humans is
23
104
No. Of linkage groups in human males and female is
```
Males = 44+X+Y = 24
Females = 44+XX = 23
```
105
No. Of linkage groups in pea plant is
7
106
In drosophila, no. Of linkage groups are
4
107
In ______ linkage, RF =0% i,e recombinants are not formed.
Complete linkage
108
In incomplete linkage, recombinants are formed in _______
Less frequency.
109
Examples of complete linkage are
Male-drosophila and female-silkmoth.
110
Characteristics of complete linkage?
No recombinants.
RF = 0%
Instead of 4 gametes, only 2 gametes are formed.
Test cross ratio is 1:1 instead of 1:1:1:1
Rare phenomenon.
111
Characteristics of incomplete linkage?
Recombinants are formed in less frequency.
All 4 types of gametes are formed.
Test cross ratio is deviated from 1:1:1:1
112
In sweet pea , obtained test cross ratio is
7:1:1:7
BL:Bl:bL:bl
113
Numericals on linkage
If M&N are incompletely linked , then recombinants will be formed though in less frequency, so the no. Of gametes will be same as we calculated 2^n where n is no. Of heterozygosities. “Solve as if incomplete linkage isn’t written in qs”.
If M&N are completely linked, consider linked genes as one heterozygosity and others independently.
*for better understanding see examples from notebook.
114
Chromosomal theory of inheritance was given by
Nilson & Stevans.
Acc, to this theory,orgs have 2 types of chr.; autosomes and sex chromosomes.
115
Genic balance theory was given by
Bridges.
Acc. to this theory, sex is determined by value of X/A ratio.
Where x= no. Of chr.
A = ploidy level of autosomes.
116
Different values of X/A represent what acc. To genic balance theory?
```
If value of X/A is
<0.5 —> super male
=0.5 —> male
B/w 0.5 & 1 —> inter-sex
=1 —> female
>1 —> super female
```
117
Whats sex-linked traits?
Genes responsible is present on sex-chromosome.
| Eg.s Haemophilia, colourblindness , DMD.
118
Sex-limited traits?
Gene responsible is present on autosomes.
Gene is expressed in ‘only one sex’.
Eg.s breast development in females, beard development in males, plumage formation in peacock.
119
Sex-influences traits?
Gene responsible is present on autosome.
Expresses ‘more in one sex’.
Eg.s paternal baldness, muscle development.
120
Holoandric traits?
Gene responsible is present on Y-chromosome.
| Eg.s, hypertrichosis (hair growth in ear), percupine males (standing hair [khade baal] ), webbed toes.
121
In sex-linked inheritance, there is variation in ratio of reciprocal cross.
T/F
True.
| Eg.s eye colour in drosophila.
122
Who suggested that recombinant frequencies can be utilised in predicting the sequence of genes on the chromosome?
A.H.Sturtevant
123
Who prepared first chromosomal map or genetic map for drosophila?
A.H.Sturtevant
124
Chromosomal theory of inheritance was proposed independently by
Sutton & boveri
125
%age of recombinant type b/w genes y & w in Drosophila?
1.3%
Rest 98.7% is parental type.
126
%age of recombinants b/w genes w & m of Drosophila?
37.2%
Rest 62.8% is parental type
127
Who used the frequency of recombination b/w gene pairs on the same chr. to measure distance b/w genes and mapped their position on the chromosome?
Alfred Sturtevant
128
Sex-linked diseases in humans is
Colour blindness & haemophilia
129
SCA, Thallasemia, phenyl ketonuria is autosomal recessive disorder.
True
130
Turner’s syndrome is due to
Monosomy of sex-chr.
44+XO
131
Klinefelter’s syndrome is due to
Trisomy of sex-chr.
44+XXY
132
Down’s syndrome is due to
Mostly due to trisomy of 21st chromosome.
