Showing posts with label Genome. Show all posts
Showing posts with label Genome. Show all posts

Sep 18, 2015

Genetics vs. Genomics

The words genetic and genomic are often used interchangeably. However, they have different and specific meanings.

Genetics is the study of heredity. It is the study of how inherited traits are passed from one generation to the next through the genes, and how new traits appear by way of genetic mutations or changes. These traits may be characteristics like eye or hair color.

Genomics is a more recent term that describes the study of all of a person's genes (the genome). Genomics is defined as the study of genes and their functions, and related techniques.

The main difference between genomics and genetics is that genetics looks at the functioning and composition of a single gene and genomics addresses all genes and their inter relationships in order to identify their combined influence on the growth and development of an organism.

Genetic information is stored in the molecule DNA
Gene refers to a specific sequence of DNA on a single chromosome that encodes a particular product. Humans have many thousands of genes, spaced across the entire set of DNA.

The word genome encompasses the entire set of genetic information across all 23 chromosome pairs, including all genes, as well as gene-modifying sequences, and everything in-between.

In the context of clinical and research settings, "genetic" testing refers to the examination of specific bits of DNA that have a known function.

Genomic testing looks for variations within large segments across the entirety of genetic material, both within and outside known functional genes. It looks at groups of genes and how active they are, such as how a cancer is likely to grow and respond to treatment.

All the genes make up the genome. Both are important because understanding more about diseases caused by a single gene using genetics and complex diseases caused by multiple genes and environmental factors using genomics can lead to earlier diagnoses, interventions, and targeted treatments. 

Jun 19, 2015

Humans and Wallabies Share DNA

A tammar wallaby is a small- or mid-sized macropod found in Australia and New Guinea. They belong to the same taxonomic family as kangaroos. One of them, Mathilda, became the first kangaroo to have her genetic code mapped.

The Australian researchers were shocked when they compared her code with a human’s. They had expected the comparison to be a mismatch, but it turned out that the genomes of the two species were more than just similar. Apart from a few differences, the genes were identical, and many of them were arranged in the same order. Both species hold large pieces of genetic information about the other.

It made more sense when the researchers also discovered that people and these bouncy marsupials had a common ancestor that lived at least 150 million years ago. Mice separated from humans only 70 million years ago, but scientists feel that kangaroos can provide more answers about human evolution when it comes to why some DNA remained the same for eons while other DNA changed. By comparing different genomes from species, unknown genes can be identified, and Matilda revealed 14 new genes never before seen in kangaroos, which might possibly also be present in humans.

Jul 8, 2011

Spit Your Age

Dr. Eric Vilain, a professor of human genetics, pediatrics and urology at the David Geffen School of Medicine at UCLA. "With just a saliva sample, we can accurately predict a person's age without knowing anything else about them." Vilain and his colleagues looked at a process called methylation – a chemical modification of one of the four building blocks that make up our DNA.

"While genes partly shape how our body ages, environmental influences also can change our DNA as we age," explained Vilain. "Methylation patterns shift as we grow older and contribute to aging-related disease."

Using saliva samples contributed by 34 pairs of identical male twins ages 21 to 55, UCLA researchers scoured the genomes and identified 88 sites on the DNA that strongly correlated methylation to age. They replicated their findings in a general population of 31 men and 29 women aged 18 to 70.

Next, the scientists built a predictive model using two of the three genes with the strongest age-related linkage to methylation. When they plugged in the data from the twins' and the other group's saliva samples, they were able to correctly predict a person's age within five years – an unprecedented level of accuracy. "Methylation's relationship with age is so strong that we can identify how old someone is by examining just two of the 3 billion building blocks that make up our genome," said first author Sven Bocklandt.