Category Archives: Human Genetics

Genetic counselling

Genetic counseling is the method of advising people and their families who are affected by or at risk of hereditary disorders. Also, it is a process to assist them to understand and adapt to the therapeutic, mental and familial suggestions of hereditary contributions to disease.

It involves talking about a genetic condition with a health professional who has qualifications in both genetics and counselling. Genetic Disorders caused by changes or mistakes in genes are inherited from one or both parents to their offspring.

The process integrates:
1. Analyse the family and medical histories to assess the chance of disease occurrence or recurrence
2. Education about genetics, its testing, management, prevention
3. Counseling to promote the informed choices and adapt to the risk or condition.

Why might you need genetic counselling?

People affected with inherited disorder or there might be a chance to get the inherited condition, they should consult Genetic Counselor as that will help them to understand more about the condition, what causes it and how they can adjust to it and plan for the better future.

Some of the genetic conditions (sometimes referred to as ‘hereditary disorders’) people talk to a genetic counsellor about is: cystic fibrosis, Down syndrome, Fragile X syndrome, Huntington’s disease, cancer, diabetes etc.

The Genetic Counseling is different from the Genetic Testing as later involves tests which you doctr does to know about the symptoms or a family history of a genetic condition. The Genetic testing can only tell you about the likelihood and risk of your passing a genetic condition on to any children that you conceive.
Pregnant Women could do diagnostic tests as part of your pregnancy check-ups and scans, to find out if their baby has a genetic disorder. These tests include amniocentesis and chorionic villus sampling or CVS.

Role of Genetic Counselor:
Genetic counselors are trained to advise you about:

  • the risk of developing specific types of cancer based on your family history
  • Genetic tests that can give one more information about the risk of certain types of cancer
  • The testing process, the limitations and accuracy of genetic tests
  • Emotional, psychological, and social consequences after knowing the test results
  • Screening Cancer and monitoring options
  • Cancer prevention
  • Diagnostic and treatment options
  • The privacy of your genetic information
  • Talking with family members about cancer risk

Blue-eyed humans have a single, common ancestor

New research reveals that people with blue eyes have (single) common ancestor. Previously we all had brown eyes, but a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a ‘switch,’ which literally turned off the ability to produce brown eyes.

The OCA2 gene codes for the P protein, which is involved in the production of melanin pigment that gives color to our hair, eyes, and skin. The “switch,” which is found within the gene adjacent to OCA2, however does not, turn off the gene totally, but rather limits its action to lessening the production of melanin within the iris successfully i.e; “diluting” brown eyes to blue. The switch’s impact on OCA2 is exceptionally specific.

In addition to having significantly less melanin in their iris than people with brown eyes, hazel eyes or green eyes, blue-eyed individuals have only a little degree of variation in their genetic coding for melanin production. Brown-eyed people, on the other hand, have significant individual variation within the area of their DNA that controls melanin production. From this the researchers conclude that all blue-eyed individuals are linked to the same ancestors and they all have inherited the same switch at exactly the same spot in their DNA.

The color of our eyes depends on the amount of melanin is present in the iris. There’s only brown color within the eye — there’s no hazel shade or green shade or blue color. Brown eyes have the highest amount of melanin within the iris, and blue eyes have the slightest.

Risks Associated With Blue Eyes

As blue eyes contain less melanin as compared to hazel, brown and green eyes they are more susceptible to damage from UV and blue light because melanin in the iris protects the back of the eye from the damage caused by UV radiation and high-energy visible (“blue”) light from sunlight and artificial sources of these rays.

Research has shown that blue eye colour is associated with a greater risk of age-related macular degeneration (AMD) and a rare but potentially deadly form of eye cancer called uveal melanoma.

For these reasons, people with blue eyes should be more cautious regarding their exposure to sunlight.

Could we use gene mutations to treat diabetes and heart disease?

Researchers say they have found a gene mutation that moderates the metabolism of sugar within the intestine, giving individuals who have the mutation a distinct advantage over those who don’t. Those with the mutation have a lower chance of diabetes, obesity, heart failure, and even death. The analysts say their finding may give the basis for drug therapies that could imitate the workings of this gene mutation, offering a potential advantage for the millions of individuals who endure with diabetes, heart disease, and obesity.

The study shows that individuals who have the characteristic gene mutation have an advantage when it comes to diet. Those who eat a high-carbohydrate diet and have this mutation will retain less glucose than those without the mutation. A high-carbohydrate diet includes such foods as pasta, bread, cookies, and sugar-sweetened beverages. Researchers said that they’re excited about this study since it helps them to clarify the interface between what we eat, what we absorb, and our chance for disease. Knowing this opens the door to improved treatments for the cardiometabolic disease.

During the study, the analysts examined the relationship between SGLT-1 mutations and cardiometabolic disease using genetic data gotten from 8,478 participants in the Atherosclerosis Risk in Communities (ARIC) study. The analysts found that almost 6 percentages of the subjects carried a mutation in SGLT-1 that causes limited impairment of glucose absorption. People with this change had a lower incidence of type 2 diabetes, were less obese, had a lower rate of heart failure, and had a lower mortality rate when compared to those without the mutation, indeed after adjusting for dietary intake.

Based on these discoveries, the researchers recommend that specifically blocking the SGLT-1 receptor could provide a way to slow down glucose uptake to anticipate or treat cardiometabolic disease and its consequences.


Neurofibromatosis_Human Genetics Meet 2019 (2)Neurofibromatosis is a rare genetic Disorder in the nervous system. In this case, benign tumors grow in the nerves and in other parts of the body which affect the growth and development of nerve cell tissue. Sometimes people with this disorder affected profoundly whereas some could barely notice the neurological problems. In this disorder is a group of three disorder in which the tumors grow in the nervous system. The three types are neurofibromatosis type 1 (NF1),type 2 (NF2) neurofibromatosis and Schwannomatosis. Neurofibromas that occur on or under the skin, sometimes even deep within the body; these are benign (harmless) tumors; however, in rare cases, they can turn malignant or cancerous.

Neurofibromatosis is often inherited (passed on by family individuals through our genes), but around 50% of individuals recently analyzed with the disorder have no family history of the condition, which can emerge spontaneously through a mutation in the genes. Once this change has taken place, the mutant gene can be passed on to future eras.

<>In NF1 side effects include light brown spots on the skin, freckles within the armpit and crotch, small bumps inside nerves, and scoliosis.
<>Tiny growths in the iris (colored area) of the eye; these are called Lisch nodules and usually do not affect eyesight.
<>Bone deformities, including a twisted spine (scoliosis) or bowed legs
Tumors along the optic nerve, which may cause eyesight problems

<>In NF2 there may be hearing loss, cataracts at a youthful age, balance issues, flesh-colored skin flaps, and muscle wasting.
<>The tumors are generally non-cancerous.

<>In schwannomatosis isn’t well-understood it is estimated that 85 percent of cases have no known cause (“spontaneous”) and 15 percent are acquired.

<>Neurofibromatosis is diagnosed using a number of tests, including:
<>Physical examination
<>Medical history
<>Family history
<>Computerized tomography (CT) scans
<>Magnetic resonance imaging (MRI)
<>Biopsy of neurofibromas
<>Eye tests
<>Tests for particular symptoms, such as hearing or balance tests
<>Genetic testing

Human genetic variation

Human genetic variation_Human Genetics Meet 2019

Human genetic variation is the hereditary contrasts in and among populations. There may be multiple variations of any given gene within the human population (alleles), a situation called polymorphism. No two people are hereditarily identical. Indeed monozygotic twins (who create from one zygote) have occasional hereditary differences due to transformations occurring during development and gene copy-number variation. Differences between people, indeed closely related individuals, are the key to strategies such as genetic fingerprinting. The study of human genetic variation has developmental significance and therapeutic applications. It can help researchers get it ancient human populace migrations as well as how human groups are naturally related to one another. For medication, think about of human genetic variation may be vital since a few disease-causing alleles happen more frequently in individuals from particular geographic districts. Modern discoveries appear that each human has an average of 60 new mutations compared to to their parents.

Causes of variation

Causes of differences between individuals include independent assortment, the exchange of genes (crossing over and recombination) during reproduction (through meiosis) and different mutational events. There are at least three reasons why hereditary variety exists between populations. The natural choice may confer an adaptive advantage to people in a particular environment if an allele provides a competitive advantage. Alleles under selection are likely to occur only in those geographic districts where they confer an advantage. A second important process is genetic drift, which is the impact of irregular changes within the gene pool, under conditions where most mutations are natural (that is, they do not appear to have any positive or negative selective impact on the organism). Finally, little migrant populaces have statistical differences—call the founder effect—from the overall populaces where they originated; when these vagrants settle new zones, their descendant populace typically vary from their population of origin.

What Is the Significance of Human Genetic Variation?

Nearly all human genetic variation is generally insignificant biologically; that is, it has no adaptive importance. A few variations (for example, a neutral transformation) modify the amino acid sequence of the resulting protein but produce no detectable change in its work. Other variation (for case, a silent transformation) does not indeed change the amino acid sequence.

Role of epigenetics in evolution of memory and learning in reference of Songbird’s

Baltimore OrioleA well-known songbird, the great tit, has discovered its genetic code, providing researchers new insight into how species adapt to an ever-changing planet. Their initial findings recommend that epigenetics — what’s on instead of what’s within the gene — might play a key role within the evolution of memory and learning. And that is not simply true for birds. An international research team led by The Netherlands Institute of Ecology (NIOO-KNAW) and Wageningen University can publish these findings in Nature Communications. “People in our field are expecting this for many years,” explain researchers Kees van Oers and Veronika Laine from The Netherlands Institute of Ecology. The reference genome of their favorite model species, the great tit, is “a powerful tool case that each one ecologist and evolutionary biologists should know about.” Coming from one Dutch bird, the genetic code of the assembled reference genome can facilitate to reveal the genetic basis of phenotypic evolution. This can be essential for understanding how wild species adapt to our ever-changing planet.

In addition to looking at the genome, the research team has conjointly determined the so-called transcriptome and methylome. The latter belongs to the sector of epigenetics: the study of what you’ll be able to inherit not in but ‘on’ your genes. Specific DNA sequences within the genome may be ‘methylated': methyl groups are added to them, modifying how the genes perform. What that research has discovered are so-called conserved patterns of methylation in those same regions, present not only in birds however additionally in humans and different mammals. It’s proof of a correlation between epigenetic processes like methylation and the rate of molecular evolution: “the more methylation, the more evolution. And so the great tit has another time proved that its role as a model species during a kind of biological research fields for over sixty years is by no means coincidental.

Population genetics

Population genetics_Human Genetics Meet 2019Population genetics looks to understand how and why the frequencies of alleles and genotypes alter over time inside and between populations. It is the branch of science that gives the most profound and clearest understanding of how developmental alter happens. Population genetics is especially relevant nowadays within the growing journey to get it the basis for genetic variation in susceptibility to complex diseases. Population hereditary qualities are personally bound up with the study of advancement and natural selection and are regularly respected as the hypothetical cornerstone of cutting-edge Darwinism. This is because the natural selection is one of the foremost vital components that can influence a population’s hereditary composition. Natural determination happens when a few variants in a population out-reproduce other variants as a result of being better adjusted to the environment, or ‘fitter’. .

Assuming the fitness differences are at least mostly due to hereditary differences, this will cause the population’s hereditary makeup to be changed over time. By considering formal models of gene frequency alter, population geneticists hence trust to shed light on the developmental process and to allow the results of distinctive developmental hypotheses to be investigated in a quantitatively precise way.

Advances in molecular science have created an enormous supply of information on the hereditary inconstancy of genuine populations, which has empowered a link to be forged between unique population-genetic models and observational data. The status of populace hereditary qualities in modern science is an interesting issue. In spite of its centrality to evolutionary hypothesis, and its historical significance, populace hereditary qualities aren’t without its critics. Population-genetic models of advancement have too been censured on the grounds that few phenotypic characteristics are controlled by genotype at a single locus, or indeed two or three loci.

In spite of the criticisms levelled against it, populace genetics has had a major impact on our understanding of how evolution works.