Presentation on Sex influenced traits. Very informative for Biology students. This presentation include the basic terminologies and have the information that how sex influenced traits are different from sex linked traits. This presentation contains information that how these traits are transferred to next generations.
There are two types of chromosomes, Autosomes and Sex chromosomes
Autosomes are those chromosomes that are not involved in sex determination.
Sex chromosomes are those chromosomes that determine the sex of an organism.
A human somatic cell has two sex chromosomes: XY in male (hetero-gametic) and XX in female (homo-gametic).
There are two types of chromosomes, Autosomes and Sex chromosomes
Autosomes are those chromosomes that are not involved in sex determination.
Sex chromosomes are those chromosomes that determine the sex of an organism.
A human somatic cell has two sex chromosomes: XY in male (hetero-gametic) and XX in female (homo-gametic).
Examples of Codominance. The best example, in this case, is the codominance blood type. ABO group is considered to be a codominant blood group where both father’s and mother’s blood group is expressed. It means that the properties of the blood groups exist in the ABO type.
Codominance is a relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.
“Incomplete dominance is a form of intermediate inheritance in which one allele for a particular trait is not expressed completely over its paired allele.” What is Incomplete Dominance? Incomplete dominance is a form of Gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype.
It shows that alleles of red and white coloured flowers were unable to dominate the other, thus resulting in incomplete dominance. Thus, the law of incomplete dominance says that when none of the two alleles exerts complete dominance over the other, the offspring will be a mixture of parents’ phenotypes. Aside from flowering plants, incomplete dominance takes place in human beings and animals as well. One such incomplete dominance example in human beings is that the growth of wavy hair.
The phenomenon in which two true-breeding parents crossed to produce an intermediate offspring (also known as heterozygous) is called incomplete dominance. ... In incomplete dominance, the variants (alleles) are not expressed as dominant or recessive; rather, the dominant allele is expressed in a reduced ratio.
Features of multiple alleles. The same genes have more than two alleles. All multiple alleles in homologous chromosomes occupy the respective loci. A chromosome or gamete only has one group allele. Each human contains only two separate gene alleles, one for each homologous pair of chromosomes carrying the gene.
More than two alternative alleles of a gene are known as multiple alleles in a population occupying the same locus on a chromosome or its homologue. ... Multiple alleles express various alternatives of one trait. Different alleles can exhibit codominance, dominance-recessive behaviour or incomplete dominance.
Allelic and Non-allelic interactions : Complete dominance; Incomplete dominance-in Four O'clock plant, Mirabilis jalapa and Snapdragon, Antirrhinum majus ; Co-dominance- MN blood group, AB blood group, Roan coat colour in shorthorn breed of cattle; Inheritance of Comb pattern in Poultry; Epistasis -Dominant - Fruit colour in Summer squash, Recessive - Coat colour in mice; Complementary gene interaction -Purple flower colour in Sweet pea (Lathyrus odoratus)
Examples of Codominance. The best example, in this case, is the codominance blood type. ABO group is considered to be a codominant blood group where both father’s and mother’s blood group is expressed. It means that the properties of the blood groups exist in the ABO type.
Codominance is a relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.
“Incomplete dominance is a form of intermediate inheritance in which one allele for a particular trait is not expressed completely over its paired allele.” What is Incomplete Dominance? Incomplete dominance is a form of Gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype.
It shows that alleles of red and white coloured flowers were unable to dominate the other, thus resulting in incomplete dominance. Thus, the law of incomplete dominance says that when none of the two alleles exerts complete dominance over the other, the offspring will be a mixture of parents’ phenotypes. Aside from flowering plants, incomplete dominance takes place in human beings and animals as well. One such incomplete dominance example in human beings is that the growth of wavy hair.
The phenomenon in which two true-breeding parents crossed to produce an intermediate offspring (also known as heterozygous) is called incomplete dominance. ... In incomplete dominance, the variants (alleles) are not expressed as dominant or recessive; rather, the dominant allele is expressed in a reduced ratio.
Features of multiple alleles. The same genes have more than two alleles. All multiple alleles in homologous chromosomes occupy the respective loci. A chromosome or gamete only has one group allele. Each human contains only two separate gene alleles, one for each homologous pair of chromosomes carrying the gene.
More than two alternative alleles of a gene are known as multiple alleles in a population occupying the same locus on a chromosome or its homologue. ... Multiple alleles express various alternatives of one trait. Different alleles can exhibit codominance, dominance-recessive behaviour or incomplete dominance.
Allelic and Non-allelic interactions : Complete dominance; Incomplete dominance-in Four O'clock plant, Mirabilis jalapa and Snapdragon, Antirrhinum majus ; Co-dominance- MN blood group, AB blood group, Roan coat colour in shorthorn breed of cattle; Inheritance of Comb pattern in Poultry; Epistasis -Dominant - Fruit colour in Summer squash, Recessive - Coat colour in mice; Complementary gene interaction -Purple flower colour in Sweet pea (Lathyrus odoratus)
Professor Stephen Breedlove presents his latest research on How do sex differences in behavior arise? at the Gender Matters interdisciplinary forum on February 26, 2016
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
3. Basic Terminologies
Alleles : An allele or allel, is one of a
number of alternative forms of the same
gene.
Autosomal chromosomes : The
autosomal chromosomes do not
determine the sex of offspring. Rather,
they contain many genes that code for
the production of thousands of
proteins.
4. Sex chromosomes : The sex
chromosomes determine the sex of
offspring. Sex chromosomes determine
whether the offspring are male or
female.
Lipoma : A lipoma is a benign tumor of
fat cells that can cause rubbery tumors
of varying size beneath the skin.
A benign tumor is a mass of cells that
lacks the ability to invade neighboring
tissue .
5. Heterozygous : The genetics term
heterozygous refers to a pair of genes
where one is dominant and one is
recessive.
6. Homozygous : The genetics term
homozygous refers to a pair of genes
where both genes are dominant or both
are recessive.
7. Testosterone : It is a steroid
hormone which is found in mammals,
reptiles, birds and other vertebrates. In
mammals, testosterone is secreted
primarily in the testicles of males and
the ovaries of females. It promotes
secondary sexual characteristics such
as increased muscle, bone mass, and
the growth of body hair.
8. Where we are heading….
Sex-linked traits are controlled by
alleles found on the sex-chromosomes.
Sex-influenced traits are controlled by
alleles on autosomal chromosomes.
9. What is a sex-influenced trait?
A sex-influenced trait is a trait controlled by a pair
of alleles found on the autosomal chromosomes
(pairs 1 through 22) but it’s phenotypic
expression is influenced by the presence of
certain hormones.
Sex-influenced traits can be seen in BOTH
sexes, but will vary in frequency between the
sexes, or in the degree of the phenotypic
expression.
Estrogen, Progesterone, Testosterone, etc.
10. Example of Sex-Influenced
Traits
Pattern Baldness
– Pattern Baldness can occur in both males
and females, however it is much more
common in males.
– Why is this?
Because the pattern baldness trait is
influenced by the hormone testosterone.
11. Pattern baldness in humans
(sometimes called “male pattern
baldness,” though the condition isn’t
restricted to males). This gene has two
alleles, “bald” and “non-bald.” The
behaviors of the products of these
genes are highly influenced by the
hormones in the individual, particularly
by the hormone testosterone.
12. . In the presence of high levels of
testosterone, the baldness allele has a
very powerful influence. In the presence
of low levels of testosterone, this allele
is quite ineffectual. All humans have
testosterone, but males have much
higher levels of this hormone than
females do. The result is that in males,
the baldness allele behaves like a
dominant allele, while in females it
behaves like a recessive allele.
15. Sex-Influenced Trait
Assume that the trait is
dominant in males but
recessive in females.
Assume all outsiders are
homozygotes.
Thus:
– DD is always affected
– dd is always normal
– Dd is affected in males, but
normal in females
16. Pattern Baldness
The combination of alleles for pattern
baldness will lead to different phenotypic
expressions depending on the sex of the
individual.
For example: Let B represent the non-bald allele
- BB genotype: non-bald in both sexes
- bb genotype: bald in both sexes
- Bb genotype: bald in men; non-bald in females
17. Pattern Baldness
The “B” allele acts as a dominant allele
in the heterozygous genotype in
females, but acts as a recessive allele
in the heterozygous genotype of the
male.
19. Try this out!
What is the probability that YOU will be
bald if your father is homozygous and
balding, and your mother is
homozygous and not balding?
Father’s genotype: bb X Mother’s genotype: BB
All offspring are Bb
If you are a male, you will be bald! If you are a
female, you will not demonstrate pattern baldness.
20. You can solve using Monohybrid
crosses
Complete the simple cross and then express
the phenotype based on whether we are
talking about males or females.
Ex. A heterozygous balding male reproduces
with a heterozygous normal female.
Do the cross and determine the phenotypic
rations for males and females
21. Let’s try a few problems involving
sex influenced traits…
A male homozygous for clubfoot reproduces
with a normal homozygous female. What are
the genotypes and phenotypes of their
children if testosterone alters the phenotypic
expression of the trait in the heterozygous
expression?
Let F represent normal feet
Let f represent clubfoot.
22. Let’s try a few problems…
Two heterozygous individuals get married
and have lots of children. The father suffers
with a painful condition called gout. What are
the parent’s genotypes? What are the
genotypes and phenotypes of the children?
Let G represent no gout, and g represent
gout.
23. How about this one:
Rheumatoid arthritis occurs more
often in females than males due to
the presence of estrogen. A
heterozygous woman marries a
heterozygous male. RR would cause
the condition in both sexes. A
homozygous recessive, rr, genotype
would prevent the disorder in both
sexes