17-The Y-Chromosome DNA testing helps in the examination of the male specific portion of the biological evidence. This is useful where small amount of male DNA is found amidst a large amount of female DNA , as in the sexual assault cases.It can also help in the missing person investigation as it extends the range of potential reference samples. Sine the Y chromosome is passed on from the fathers to their sone (unchanged, except in the case of some mutations), therefore all the males of the same paternal lineage will possess common Y chromosome haplotype. A set of Short tandem repeats (STR) are found on the male specific Y chromosome.The coding genes found on the short arm of the Ychromosome are vital to male sex determination, spermatogenesis andother male related functions. The Y-STRs are polymorphic among the nonrelated males. Sometimes when sepoarating the mal ecomponent and the female component becomes difficult, then the YSTRs help in the determination. Since The Y-STRs are not present in the females, therefore in a case where the male and female are involved, it becomes clear that as the Y-STRs are present the male component is easily detected as only this part will be amplified in the PCR. The YSTRs are also helpful when a number of males are involved. As regular STRs cause masking effect the YSTR will help to identify all the males who have contributed to the evidence. ADVANTAGES- 1. extremely discriminating. 2. Extremely sensitive.e. low amounts of DNA can be used for determination. 3. Not onlu body fluids, but alsp touched materials or handled surfaces, where skinn cells ahev been left can be used for DNA profiling. 4. Multiple testing systems ar available, which increases the likelyhood of successfully generating DNA profiles. 5. Apart from standart=d STR enem mt DNA or YSTRs are used for profiling. 6. With the presence of the current technologies, from amidst mixed DNA samples, the DNA of a particular individual can be profiled. LIMITATIONS 1. Random match probability cannot be excluded. 2. Sometimes even when crime is not committed, we do get ,low levels of DNA on surfaces. 3.The important question while dealing with low DNA quantity is that whether the DNA that was deposited was deposited during the crime or at some other time. 4.Searching evidence is challenging. 5.Sometimes finding the evidence is altogether impossibl. 6. In case of mtDNA /T STRs , as they are passed on from generation to generation either from fathers to sons or mothers to daughters and son, therefore sometimes unrelated persons are also share the same profile. 7. DNA mixtures are very complex. 8.Interpretation is required in many cases. 16- from Cyanobacterial to humans, many terristrial organisms have acquired the circadian rhythms to adapt to sunlight to increase their survival rate.Circadian Rhythm is a biological clock that displays an endogenous, entrainable oscillation of 24 hours.Thesse oscillations are driven by circadian clocks. PULSE CHASE EXPERIME.

1. 17-The Y-Chromosome DNA testing helps in the examination of the male specific portion of the
biological evidence. This is useful where small amount of male DNA is found amidst a large
amount of female DNA , as in the sexual assault cases.It can also help in the missing person
investigation as it extends the range of potential reference samples. Sine the Y chromosome is
passed on from the fathers to their sone (unchanged, except in the case of some mutations),
therefore all the males of the same paternal lineage will possess common Y chromosome
haplotype.
A set of Short tandem repeats (STR) are found on the male specific Y chromosome.The coding
genes found on the short arm of the Ychromosome are vital to male sex determination,
spermatogenesis andother male related functions. The Y-STRs are polymorphic among the
nonrelated males.
Sometimes when sepoarating the mal ecomponent and the female component becomes difficult,
then the YSTRs help in the determination. Since The Y-STRs are not present in the females,
therefore in a case where the male and female are involved, it becomes clear that as the Y-STRs
are present the male component is easily detected as only this part will be amplified in the PCR.
The YSTRs are also helpful when a number of males are involved. As regular STRs cause
masking effect the YSTR will help to identify all the males who have contributed to the
evidence.
ADVANTAGES-
1. extremely discriminating.
2. Extremely sensitive.e. low amounts of DNA can be used for determination.
3. Not onlu body fluids, but alsp touched materials or handled surfaces, where skinn cells ahev
been left can be used for DNA profiling.
4. Multiple testing systems ar available, which increases the likelyhood of successfully
generating DNA profiles.
5. Apart from standart=d STR enem mt DNA or YSTRs are used for profiling.
6. With the presence of the current technologies, from amidst mixed DNA samples, the DNA of
a particular individual can be profiled.
LIMITATIONS
1. Random match probability cannot be excluded.
2. Sometimes even when crime is not committed, we do get ,low levels of DNA on surfaces.
3.The important question while dealing with low DNA quantity is that whether the DNA that
was deposited was deposited during the crime or at some other time.
4.Searching evidence is challenging.
5.Sometimes finding the evidence is altogether impossibl.

2. 6. In case of mtDNA /T STRs , as they are passed on from generation to generation either from
fathers to sons or mothers to daughters and son, therefore sometimes unrelated persons are also
share the same profile.
7. DNA mixtures are very complex.
8.Interpretation is required in many cases.
16- from Cyanobacterial to humans, many terristrial organisms have acquired the circadian
rhythms to adapt to sunlight to increase their survival rate.Circadian Rhythm is a biological clock
that displays an endogenous, entrainable oscillation of 24 hours.Thesse oscillations are driven by
circadian clocks.
PULSE CHASE EXPERIMENT
A pulse chase analysis is a method of examining a cellular process occuring over time by
successively exposing the cells toa labelled compound (pulse) and then to the same compound in
an unlabelled form (chase).
A selected cell is exposed to a labelled compound that is to be incorporated into a molecule or
system that is studied. The compound then undergoes the metabolic pathways and is used in the
synthesis of the product studied. Shortly after the introduction of the labelled compound,excexx
of the same but the unlabelled substance is introduced into the environment.
This is useful for determining the activity of certain cells over a ,long period of time.
This has been used to study Protein Kinase C, Ubiquitin and many other products.
PLURIPOTENT cells- can give rise to all of the cells that make up the body eg-embryonic cells.
TOTIPOTENT CELLS- can form all the cell tyoes in a body plus the extre-embryonic cells or
the placental cells.
Toripotent cells can give rise to both placental and embryo.
Solution
17-The Y-Chromosome DNA testing helps in the examination of the male specific portion of the
biological evidence. This is useful where small amount of male DNA is found amidst a large
amount of female DNA , as in the sexual assault cases.It can also help in the missing person
investigation as it extends the range of potential reference samples. Sine the Y chromosome is
passed on from the fathers to their sone (unchanged, except in the case of some mutations),
therefore all the males of the same paternal lineage will possess common Y chromosome
haplotype.
A set of Short tandem repeats (STR) are found on the male specific Y chromosome.The coding
genes found on the short arm of the Ychromosome are vital to male sex determination,
spermatogenesis andother male related functions. The Y-STRs are polymorphic among the

3. nonrelated males.
Sometimes when sepoarating the mal ecomponent and the female component becomes difficult,
then the YSTRs help in the determination. Since The Y-STRs are not present in the females,
therefore in a case where the male and female are involved, it becomes clear that as the Y-STRs
are present the male component is easily detected as only this part will be amplified in the PCR.
The YSTRs are also helpful when a number of males are involved. As regular STRs cause
masking effect the YSTR will help to identify all the males who have contributed to the
evidence.
ADVANTAGES-
1. extremely discriminating.
2. Extremely sensitive.e. low amounts of DNA can be used for determination.
3. Not onlu body fluids, but alsp touched materials or handled surfaces, where skinn cells ahev
been left can be used for DNA profiling.
4. Multiple testing systems ar available, which increases the likelyhood of successfully
generating DNA profiles.
5. Apart from standart=d STR enem mt DNA or YSTRs are used for profiling.
6. With the presence of the current technologies, from amidst mixed DNA samples, the DNA of
a particular individual can be profiled.
LIMITATIONS
1. Random match probability cannot be excluded.
2. Sometimes even when crime is not committed, we do get ,low levels of DNA on surfaces.
3.The important question while dealing with low DNA quantity is that whether the DNA that
was deposited was deposited during the crime or at some other time.
4.Searching evidence is challenging.
5.Sometimes finding the evidence is altogether impossibl.
6. In case of mtDNA /T STRs , as they are passed on from generation to generation either from
fathers to sons or mothers to daughters and son, therefore sometimes unrelated persons are also
share the same profile.
7. DNA mixtures are very complex.
8.Interpretation is required in many cases.
16- from Cyanobacterial to humans, many terristrial organisms have acquired the circadian
rhythms to adapt to sunlight to increase their survival rate.Circadian Rhythm is a biological clock
that displays an endogenous, entrainable oscillation of 24 hours.Thesse oscillations are driven by
circadian clocks.
PULSE CHASE EXPERIMENT
A pulse chase analysis is a method of examining a cellular process occuring over time by

4. successively exposing the cells toa labelled compound (pulse) and then to the same compound in
an unlabelled form (chase).
A selected cell is exposed to a labelled compound that is to be incorporated into a molecule or
system that is studied. The compound then undergoes the metabolic pathways and is used in the
synthesis of the product studied. Shortly after the introduction of the labelled compound,excexx
of the same but the unlabelled substance is introduced into the environment.
This is useful for determining the activity of certain cells over a ,long period of time.
This has been used to study Protein Kinase C, Ubiquitin and many other products.
PLURIPOTENT cells- can give rise to all of the cells that make up the body eg-embryonic cells.
TOTIPOTENT CELLS- can form all the cell tyoes in a body plus the extre-embryonic cells or
the placental cells.
Toripotent cells can give rise to both placental and embryo.