Homeobox genes are a family of genes that encode transcription factors and play a key role in regulating embryonic development and cell differentiation. They were first discovered in 1983 in fruit flies and contain a DNA sequence called the homeodomain that provides instructions for protein production. In humans, there are over 200 homeobox genes located on every chromosome. Homeobox genes establish body patterns and regionalization during development through processes like polarity, positional information, and regulation of genes involved in cell adhesion, migration, proliferation and differentiation. Mutations in certain homeobox genes can lead to developmental disorders and anomalies.
hox genes and its role in development both in human and drosophila . homeotic genes. homeobox genes. developmental biology. different types of homeotic genes in drosophila and human. deficiencydiseases due to lack of hox genes in human
Welcome to the world of Homeotic genes. In this presentation I talk about the interesting history behind homeotic genes as to how it was discovered. Also, the various deformities in Drosophila related to mutations in homeotic genes and the characteristics of homeotic genes. I also talk about hox genes in humans and their function.
hox genes and its role in development both in human and drosophila . homeotic genes. homeobox genes. developmental biology. different types of homeotic genes in drosophila and human. deficiencydiseases due to lack of hox genes in human
Welcome to the world of Homeotic genes. In this presentation I talk about the interesting history behind homeotic genes as to how it was discovered. Also, the various deformities in Drosophila related to mutations in homeotic genes and the characteristics of homeotic genes. I also talk about hox genes in humans and their function.
It is the fundamental law of population genetics and provides the basis for studying Mendelian populations ( Mendelian population: A group of sexually inbreeding organisms living within a circumscribed area). It describes populations that are not evolving.
A cytological technique to detect the nature of adjacent chromosomal regions by using different staining technique assisted with some pre treatment of metaphase chromosomes prepared on the slides
This presentation summarizes some of the most popular neural differentiation protocols. It also contains some of the most recent developments in these protocols including small molecule based methods.
cell commitment and differentiation, stem cell,types of differentiationshallu kotwal
The commitment of cells to specific cell fates and their capacity to differentiate into particular kinds of cells.
Cellular differentiation is the process in which a cell changes from one cell type to another. Usually, the cell changes to a more specialized type. Differentiation occurs numerous times during the development of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types. Differentiation continues in adulthood as adult stem cells divide and create fully differentiated daughter cells during tissue repair and during normal cell turnover.
Basics of Undergraduate/university fellows
Crossing over is exchange of strictly homologous segments of a genome between their
respective non-sister chromatids during cell division, which results in chromosomal
recombinations of linked genes in daughter cells.
Cell cell hybridization or somatic cell hybridizationSubhradeep sarkar
What is Cell-Cell Hybridization?
History
More about Somatic cell Hybridization
Mapping of genes by somatic cell Hybridization
Hybridoma technology
Other Applications of Somatic Cell Hybridization
Maternal effects are the influences of a mothers genotype on the phenotype of her offspring. It results from the asymmetric contribution of the female parent to the development of zygotes.
In terms of chromosomal genes, both male and female parents contribute equally to the zygote. The female parent contributes to the zygotes initial cytoplasm and organelles. Sperm rarely contribute anything other than chromosomes. Therefore zygotic development begins within a maternal medium and hence the maternal cytoplasm directly affects zygotic development.
It is the fundamental law of population genetics and provides the basis for studying Mendelian populations ( Mendelian population: A group of sexually inbreeding organisms living within a circumscribed area). It describes populations that are not evolving.
A cytological technique to detect the nature of adjacent chromosomal regions by using different staining technique assisted with some pre treatment of metaphase chromosomes prepared on the slides
This presentation summarizes some of the most popular neural differentiation protocols. It also contains some of the most recent developments in these protocols including small molecule based methods.
cell commitment and differentiation, stem cell,types of differentiationshallu kotwal
The commitment of cells to specific cell fates and their capacity to differentiate into particular kinds of cells.
Cellular differentiation is the process in which a cell changes from one cell type to another. Usually, the cell changes to a more specialized type. Differentiation occurs numerous times during the development of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types. Differentiation continues in adulthood as adult stem cells divide and create fully differentiated daughter cells during tissue repair and during normal cell turnover.
Basics of Undergraduate/university fellows
Crossing over is exchange of strictly homologous segments of a genome between their
respective non-sister chromatids during cell division, which results in chromosomal
recombinations of linked genes in daughter cells.
Cell cell hybridization or somatic cell hybridizationSubhradeep sarkar
What is Cell-Cell Hybridization?
History
More about Somatic cell Hybridization
Mapping of genes by somatic cell Hybridization
Hybridoma technology
Other Applications of Somatic Cell Hybridization
Maternal effects are the influences of a mothers genotype on the phenotype of her offspring. It results from the asymmetric contribution of the female parent to the development of zygotes.
In terms of chromosomal genes, both male and female parents contribute equally to the zygote. The female parent contributes to the zygotes initial cytoplasm and organelles. Sperm rarely contribute anything other than chromosomes. Therefore zygotic development begins within a maternal medium and hence the maternal cytoplasm directly affects zygotic development.
presented by HAFIZ M WASEEM
university of education LAHORE Pakistan
i am from mailsi vehari and studied in lahore
bsc in science college multan
msc from lahore
Evolutionary Genetics by: Kim Jim F. Raborar, RN, MAEd(ue)Kim Jim Raborar
This presentation was created as a partial fulfillment of the requirements in the subject Advanced Genetics. Everything that was here were kinda symbolic. I mean, you could recognize that this was a product of so much data interpretation. I therefore suggest you read and read a lot first before you go back to this presentation. Or you could just contact me so i could send you the key-pointers.
Have a super nice day.
Kimy
HUMAN DEVELOPMENT
Chapter 8
PSYCHOLOGY DEBORAH M. LICHT MISTY G. HULL COCO BALLANTYNE
1
Voices
GIRL WITH POTENTIAL
Ericka Harley was 16 years old and starting her junior year of high school when she found out she was pregnant.
Her mother, Joan, was disappointed to discover that her daughter, an honor-roll student, would soon be a mom; she had hoped Ericka might attend college and enjoy a successful career.
Would Ericka ever make it to college?
The Study of Human Development (part 1)
DEVELOPMENTAL PSYCHOLOGY
Refers to field of psychology that examines physical, cognitive, and socioemotional change
The Study of Human Development (part 2)
Socioemotional development
Refers to social behaviors, emotions, and changes experienced in relationships, feelings, and overall disposition
Physical development
Involves maturation wherein the body follows a universal, biologically driven progression in a generally predictable pattern
Cognitive development
Includes changes in memory, problem solving, decision making, language, and intelligence that tend to follow a universal course early in life and considerable variability with age
The Study of Human Development (part 3)
BIOPSYCHOSOCIAL PERSPECTIVE
Recognizes contributions and interplay of biological, psychological, and social forces facing human development
THREE MAJOR THEMES OR DEBATES
Stages or continuity
Hereditary and environmental influences
Stability and change
5
The Study of Human Development (part 4)
RESEARCH METHODS USED TO STUDY DEVELOPMENTAL PROCESSES
Cross-sectional method
Examines people of different ages at a single point in time
Longitudinal method
Examines one sample of people over a period of time to determine age-related changes
Cross-sequential method
Examines groups of people of different ages, following them across time
6
Genetics, Conception, and Prenatal Development (part 1)
CHROMOSOMES AND GENES
Chromosomes
Inherited threadlike structures composed of deoxyribonucleic acid (DNA)
Deoxyribonucleic acid (DNA)
Molecule that provides the instructions for the development and production of cells
Gene
Specified segment of a DNA molecule
Genetics, Conception, and Prenatal Development (part 2)
CHROMOSOMES, DNA, AND GENES
Every cell in your body, except red blood cells and sex cells (sperm or egg), contains a full set of 23 chromosome pairs like those shown here.
These 23 chromosome pairs contain the full blueprint for you as a complete, unique person. The primary component of each chromosome is a single, tightly wound molecule of DNA. Within that DNA are around 21,000 genes (Pennisi, 2012, September 5), each determining specific traits such as hair texture. Note the sex chromosomes (X and Y) on the lower right, indicating that the sex is male. Photo: CNRI/Science Source.
8
Genetics, Conception, and Prenatal Development (part 3)
CHROMOSOMES AND GENES
How exactly did you get your genes from your biological parents?
...
cell lineage , cell fate - diverse class of cell fate, cell fate in plant meristem, mammalian development cell fate, nutritional effects on epigenetics, epigenetics of plants,
control of cell fate.
The thorax refers to the region which forms a major part of the appendicular skeleton. Knowledge of its surface anatomy is essential for surgical techniques, to say the least.
A cell is in similitude with a fenced house that has a gate. The cell membrane serves to a cell what function does to a house. Just like a gate allows for passage to and fro the house, the cell membrane has adaptions that allow communication between the internal environment with the external environment.
Savants are non-neurotypical persons with extraordinary islands of genius. These abilities usually stands in jarring justaposition to their overall mental handicap. This begs the question of how much untapped potential is earthed within neurotypical persons.
4. What is geneexpression?
Gene expression is the
activation of a gene that results
in a polypeptide or protein.
Transcription factors
5. What are HomeoboxGenes?
Homeoboxgenesare a large family of similar genes that
direct the formation of many body structures during early
embryonic development.
The gene is a unit of information that encodes a genetic
characteristic.
7. Homeodomain
Homeobox genes contain a
particular DNA sequence that
provides instructions for making a
string of 60 protein building blocks
(amino acids) known asthe
homeodomain.
9. Human HomeoboxGenes
In humans, the homeobox gene family
contains anestimated 235 functional
genes and 65 pseudogenes.
Homeobox genes are present on every
human chromosome, and they often
appear in clusters.
Examples include: HOX, PAX, MSX, DLX
11. Four general phasesfor body
formation
1. Organizebodyalong
major axes
2. Organizeinto smaller
regions (organs, legs)
3. Cells organize to
produce body parts
4. Cells themselves
change morphologies
and become
differentiated
12. ModusOperandi
Polarity
•Even before fertilization an egg has a gradientof proteins that help to
establish its polarity (which end becomesthe head or anterior and which
is the tail, posterior)
•After fertilization “Maternal Effect” genes reinforce this polarity and also
establish the dorsal (back)and ventral (belly) orientation
•Polarity is the formation of the axis by which the embryo differentiates
13. Positional informationduring development
• Eachcell receives positional
information that tells it where to go
and what to become.
• Cells may respond by
1. Cell division,
2. cell migration,
3. cell differentiation or
4. cell death (apoptosis)
14.
15. Summary
Three-dimensional patterning and body plan formation during
embryogenesis arelargely attributable toaction of homeobox genes,dueto
their capacity to spatiotemporally regulate the basic processes of
differentiation, proliferation, and migration (Manley and Levine, 1985; Han
etal., 1989).
Homeobox genes can regulate genes responsible for cell adhesion,
migration, proliferation, growth arrest, and the expression of cytokines
neededfor extracellular matrix interactions (Graba etal.,1997; Svingen and
Tonissen, 2006; Hueber etal., 2007)
18. Aniridia
Aniridia is an eye disordercharacterized by a
complete or partial absence of the colored part
of the eye (the iris).
Aniridia is causedbymutations in
the PAX6gene.The PAX6geneprovides
instructions for making a protein that is
involved in the early development of the eyes,
brain and spinal cord (central nervous system),
and the pancreas.
20. References
• McGinnis W, Levine M, Hafen E, Kuroiwa A,GehringW (1984)."Aconserved DNAsequence inhomoeotic genes
of the Drosophila Antennapedia and bithorax complexes". Nature308(5958):428–33.
• Scott M, WeinerA (1984)."Structural relationships among genes that control development: sequence homology
between the Antennapedia, Ultrabithorax, and fushi tarazu loci of Drosophila". Proceedings of the National
Academy of Sciencesof the UnitedStates of America 81 (13): 4115–9
• Graba, Y.,Aragnol, D., and Pradel, J. (1997).Drosophila Hox complex downstream targets and the function of
homeotic genes. Bioessays 19,379–388
• Han, K., Levine, M. S., and Manley,J. L. (1989). Synergisticactivation and repression of transcription by Drosophila
homeobox proteins. Cell 56,573–583.
• Manley,J. L., and Levine, M. S. (1985).The homeo box and mammalian development. Cell 43,1–2. doi:
10.1016/0092-8674(85)90002-9
• Hueber, S. D., Bezdan, D., Henz, S. R., Blank, M., Wu, H., and Lohmann,I. (2007).Comparative analysis of Hox
downstream genes inDrosophila. Development 134,381–392.
• Svingen, T., and Tonissen, K. F. (2006).Hox transcription factors and theirelusive mammalian gene targets.
Heredity (Edinb.) 97, 88–96.
Editor's Notes
The expression of some genes results in the production of a protein that can turn on or switch off other genes.
Every organism has a unique body pattern because of the influence of HOMEOBOX genes.
These specify how different areas of the body develop their individual structures, eg. Arms, legs etc
Homeobox genes were discovered when geneticists studying fruit flies found mutants with legs growing where their antennae should be and 2 sets of wings instead of 1.
Homeotic genes are regulatory genes that determine where certain anatomical structures, such as appendages, will develop in an organism during morphogenesis.
These seem to be the master genes of development
For example, mutations in the HOX group of homeobox genes typically cause limb malformations. Changes in PAX homeobox genes often result in eye disorders, and changes in MSX homeobox genes cause abnormal head, face, and tooth development. Additionally, increased or decreased activity of certain homeobox genes has been associated with several forms of cancer later in life.
Once the orientation is in place other genes are switched on
Segmentation occurs driven by Gap genes, Pair rule Genes and Segmentation genes
Finally the Homeotic Selector genes are switched on
These control the final specialised development of each segment
See Page 114 Text book
Each cell in the body must become the appropriate cell type based on its relative position.