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By the end of this section, you will be able to:
  • Define genomics
  • Describe genetic and physical maps
  • Describe genomic mapping methods

Genomics is the study of entire genomes, including the complete set of genes, their nucleotide sequence and organization, and their interactions within a species and with other species. Genome mapping is the process of finding the locations of genes on each chromosome. The maps created by genome mapping are comparable to the maps that we use to navigate streets. A genetic map    is an illustration that lists genes and their location on a chromosome. Genetic maps provide the big picture (similar to a map of interstate highways) and use genetic markers (similar to landmarks). A genetic marker    is a gene or sequence on a chromosome that co-segregates (shows genetic linkage) with a specific trait. Early geneticists called this linkage analysis. Physical maps present the intimate details of smaller regions of the chromosomes (similar to a detailed road map). A physical map    is a representation of the physical distance, in nucleotides, between genes or genetic markers. Both genetic linkage maps and physical maps are required to build a complete picture of the genome. Having a complete map of the genome makes it easier for researchers to study individual genes. Human genome maps help researchers in their efforts to identify human disease-causing genes related to illnesses like cancer, heart disease, and cystic fibrosis. Genome mapping can be used in a variety of other applications, such as using live microbes to clean up pollutants or even prevent pollution. Research involving plant genome mapping may lead to producing higher crop yields or developing plants that better adapt to climate change.

Genetic maps

The study of genetic maps begins with linkage analysis    , a procedure that analyzes the recombination frequency between genes to determine if they are linked or show independent assortment. The term linkage was used before the discovery of DNA. Early geneticists relied on the observation of phenotypic changes to understand the genotype of an organism. Shortly after Gregor Mendel (the father of modern genetics) proposed that traits were determined by what are now known as genes, other researchers observed that different traits were often inherited together, and thereby deduced that the genes were physically linked by being located on the same chromosome. The mapping of genes relative to each other based on linkage analysis led to the development of the first genetic maps.

Observations that certain traits were always linked and certain others were not linked came from studying the offspring of crosses between parents with different traits. For example, in experiments performed on the garden pea, it was discovered that the color of the flower and shape of the plant’s pollen were linked traits, and therefore the genes encoding these traits were in close proximity on the same chromosome. The exchange of DNA between homologous pairs of chromosomes is called genetic recombination    , which occurs by the crossing over of DNA between homologous strands of DNA, such as nonsister chromatids. Linkage analysis involves studying the recombination frequency between any two genes. The greater the distance between two genes, the higher the chance that a recombination event will occur between them, and the higher the recombination frequency between them. Two possibilities for recombination between two nonsister chromatids during meiosis are shown in [link] . If the recombination frequency between two genes is less than 50 percent, they are said to be linked.

Questions & Answers

What is the causes of Evolution
Farouk Reply
ደደብ ይሄያቅትሀል😏😡 dull😡😡😡😡😡😝😝😝😝😝😝
Eyiba
who is the first person who discover the cell
Etornam Reply
what's the difference between DNA and RNA
moffat Reply
DNA is double strained And RNA is singled strained
Only
what is a fungi
Anaba Reply
What is meant by adaptation?
Agbesi Reply
who is the father of evolution
Ferkah Reply
Charles D
Dr
complete the table below based on the levels of biological organization
Lovely Reply
Give me Examples of living thing which have 2 or more flagella?
Mahesh Reply
insect and plants
qax
bacteria and chlamydompnas
Berhanu
reproduction it's full meaning
Gift Reply
full meaning of ATP
Gifty
A life process in which living things increase their population through sexual or non sexual intercouse
Danisha
please explaination
Daniel
Gifty ATP means Adenosine tri phosphate
Mahesh
the process by which organisms produce their own kind.
Berhanu
who is the father of Biology
Ferkah
reproduction is the process where living organisms producess their offspring
jerry Reply
what is reproduction
Nmesoma Reply
why some kinds of students are failed
Ahmadi Reply
lack of concentration
Faith
lack of guidance and counseling
ali
what's the divination of openstax
John
don't mind about reading
aine
lack of focus
Afolayan
Inability to study at their own pace.📒
Agbesi
Inability to study at their own pace.📒
Agbesi
What is the meaning of optic
Kisaky Reply
Giving a specific section of the alimentary canal,describe 3 ways in which physical digestion occurs.
Kisaky
mouth when chewing
ephraim
what is population
Ivy Reply
total number of people living in an area
FILDA
a number of people lives in one catigorize area or named area
Oburak
total number of people living in a specific geographical area.📕
Agbesi
total number of people living in a specific geographical area.📕
Agbesi
what is a cell
Chiko Reply
basic and functional unit of life
Edwin
cell is tissues that makes up functional life in human or un animal.
Oburak
is the smallest basic unit of life.
Kisaky
Is the smallest baic unit. o
Kisaky
why cell is very important to human body
Ahmadi
what is diffusion
Henry
diffusion is a process of mix of particles from higher concentration to the lower one,to make the body functional normal
Adam
what is effusion
Mahesh

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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