Genetics Notes
Delve into the world of genetics with these thorough and detailed notes. Covering genetic mutations, and modern genetic technologies, this resource simplifies complex topics for easy understanding.
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Clear explanations of genetic principles.
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Genetics Summary How active are genes Homozygous
the same
of DNA but If the pair of alleles are
A branch Of BIOLOGY that studies heredity x x each full compliment
cell has a
variation in organisms only genes that are needed are activated
( others are suppressed )
It explains the similarities t differences btw .
X that different genes are activated in diff
Heterozygous
parents and their offspring cells creating specific proteins that give
if the pair of alleles are different
a particular cell Its character
on of traits / Characteristics ( bone cells brain cells ) haploid Cn ]
Heredity → palling ,
gametes
L%MhB→④
O•
from one generation to the next
embryo
× some gene , play a role in early development
UV
Gregor Mendel →
" father Of genetics
"
of the embryo X then become inactive fuses
⑨
after • -•
fertilisation
Austrian monk
¥7
→
ab chromosomes
[ 2990 te = 2 alleles for each gene ]
body cells
first breakthrough in heredity → investigating Housekeeping genes →
genes are active in
an
transfer of characteristics from one generation certain cell , and make proteins needed
to the next
( Genet )
for basic need ,
different forms for the same trait
•
genes are passed from off →
of Dominant and recessive alleles
+ sexual reproduction combines the genes
unique but the same offspring
A high amount of genes are non -
coding Gene
to produce , Alternative Alleles
genet ( don't code for proteins x occur
in between the coding sections ) TE ETE
Genes →
part of DNA molecule in chromosome) eye colour
Hox genes → matter control genes , det way
pig q.iq#* *iE ITIiq
H H
,
¥,
X each chromatid 11 made up of one hell cat DNA the body develops from a Ilngle zygote hair colour
molecule , each DNA molecule is made up of a
series of genes epigenetics → the control of genes BB ( homozygous)
Genotype :
.
x a gene is a section of DNA ( series of nucleotide 11 ( the Human EPI genome Project aims to
phenotype :
Black
{ oat
bales ) that controls a heredity characteristic document what switched genes on/off )
&
Its a base unit of heredity in living organ 11Mt A mono hybrid cross is a cross between parents
with different alleles for a single gene
A- He let →
genes responsible for controlling
r.mo.me#Yfapq&E$pfyqcentromere
version of a characteristic
different
! !!! !!!!!
" mo " ""
cunrnodmoinomthee
" same "" " " "
"
.ae . " " " are mneme.
Allele l of 2 more forms of
DNA
or a gene p, -
parent Generation
× ,
chromatid Fi -
First Filial generation of offspring
each chromosome hat 700-7000 genes
A- Hell I are represented by letter f- z -
second final generation of offspring
all somatic cell I have an exact copy of all genes
in that organism
mature red blood cells have no nuclei , so
no alleles are patted from parent to offspring punnet square
genes or chromosomes
by way of chromosomes In the gametes
Tt Parent Tt
( meiosis ) parent
Alleles → there are 2 Kindt of chromosomes
( paternal and maternal ) each cell contains
/I
T t
z of each kind of gene ( before replication ) Gametes
me , o , , , , chromosome
and these genes are known as alleles
sedpfffefteh.me:9 ,,
TT Tt
Gene pool → set of all genes / genetic information Tt tt
of sexually reproducing Melo Ill 11 Chromatids
in a population Tt i tt
Genotypes TT i
organisms separated into different cells :
4 haploid gametes ( half B allele , half b allele ) LT : ¥ :
at
l i 2 : l
high genetic diver 'll Y
large gene pool →
-
summary of me 10111 showing how alleles are
+ A chance of survival segregated Tall i short
Phenotypes :
small gene pool →
genetic diversity
low Zi : I
+ A possibility of extinction 3 : I
Genotype → made of all genes organisms
carry on their chromosomes
( Inherited from parents )
Phenotype → the physical appearance of
an organism ( tallness 1 hair colour )
, Monohybrid inheritance Red-green colour blindness Polygenetic inheritance
More than one pair of alleles responsible for
the genes that produce photo pigments -
single trait
different wavelengths of light)
a
( sensitive to
parental
Generation
are carried on the X chromosome
Titian) ticshort) If the gene is missing or damaged , certain photo Continuous variation
T t
pigment , are affected
the more pairs of alleles that control a characteristic
T t # of possible combinations
→ the larger the
Tt
Hoene ration
and the greater the variety of phenotypes
µ§
Genotype All Tt X
All tall Mating ) unaffected
phenotype carrier father
T t mother
µ
t T
+ pay , .
→ he ,gn , + µ , n co , our + meta bone rate
, ,
by poly genetic inheritance
µ
t TT t = controlled
yet
a.
other , = co , ou , ,n wheat * ma , , + fleece weigh ,
Mendel's principles of inheritance mutagen → factor , that increase the rate of
mutations ( environment / viruses )
Mendel 't law of segregation → allele pairs
segregate during me 10515 so that gametes unaffected
havea single allele for each characteristic carrier affected unaffected
daughter son daughter
son
Somatic mutations → occur in body
cells and aren't transmitted to the
Mendel 's law of dominance → in a cross of
parents pure for contrasting traits , only the
dominant trait will appear in the phenotype next generation
Recessive traits are masked by dominant allele can cause cells to become malignant → cancer
in plants → can be transmitted by vegetative propagate
( budding )
Mendel 's law of independent Assortment → alleles
of different genes segregate independently and Gametic mutations → occur in
randomly of one another during the formation of
gametes reproductive organs
(ovaries,testis,anthers,embryo sacs) and
dominant produce changes to the genes in the
Test cross
cross an unknown
gametes germ line mutations lead to variation
several times with an
organism
individual showing recessive phenotype
-
the offspring
€
Tall
Phenotype : in
¥
Genotype i
Tt or TT eventually new species evolve through speciation
Neutral mutations
these mutations do not affect an organisms life
×
i short
Phenotype but
every individual has some mutations not
Genotype : tt
all are visible in the
phenotype
TEST CROSS Haemophilia
genetically determined
condition of
rare ,
frequent excessive bleeding
,
( blood clots slowly) some genes do change
the
physical features of
the body , but don't seriously affect the body 's
t t t t H → allows blood clotting
functioning ( tongue rollers)
h doesn't allow normal blood
T Tt Tt T Tt Tt →
clotting
Beneficial mutations
t tt T Tt Tt
ft genotype XHY X
h
Y A small t -
of mutations result in a change
in the phenotypes .
If the change results in
Heterozygous Phenotype normal haemophilia C better adaptation new or unfavourable
Heterozygous (tall) 100-1 to
50% .
" H H h will have the
X x X x over time → whole population
new genotype t speciation occurred
Sex chromosomes normal normal but carrier
have more or tell the h condition caused a natural abortion rates
•
22 pairs of chromosome ) x
h
x → Due to rapid production ,
beneficial Mut .
same shape ( homologous ) AUTOSOMES occur most often
amongst viruses x bacteria
2 chromosomes ( making 23rd pair )
• up are
( multi -
resistant superbugs)
different in shape ( sex chromosome ) ) GONOIOMES H
X Xh
- -
- -
.
IX! ! maaatrrbert
" " " ' ← ""
sex chromosome X X X X
longer → Beneficial mutation =
peppered moth
shorter sex chromosome → Y y XHY
/Xh ← haemophilia c
Females XX Males XY
( Homo gametic) ( hetero gametic )
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