Glossary - B |
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Backcross
| What it's not: |
A more dastardly version of the double-cross |
| What it is: |
If you want to increase the frequency of a characteristic, you can cross (mate) a hybrid back to a parent or the genetic equivalent of a parent. This is what a backcross is. The term is also used to describe the two step process of an outcross (to get the hybrid) and then a backcross. |
Base Pair
| What it's not: |
Immoral figure skaters |
| What it is: |
A base is a basic (duh) component of a nucleic acid. Bases come in two basic versions: pyrimidines and purines. DNA contains the pyrimidines thymine and cytosine plus the purines adenine and guanine. Attached like snap fasteners, these bases form base pairs along the length of the DNA helix. Adenine (A) pairs with thymine (T), while guanine (G) pairs with cytosine (C). In RNA uracil replaces thymine in the pairing with adenine. |
Bioinformatics
| What it's not: |
Facial spasms from learning what your DNA says. |
| What it is: |
Bioinformatics is the science of managing and analyzing biological information, usually with advanced computing techniques. |
BLAST
| What it's not: |
What you shouldn’t have the night before an exam |
| What it is: |
BLAST stands for Basic Local Alignment Search Tool. (Blast! Yet another acronym!) Anyway, BLAST is a computer program that compares sequences and calculates the statistical significance of matches. When you enter your query sequence, the program searches public biological sequence data bases for sequence similarities. The program has several versions, two of them being N (a nucleotide search) and P (a protein search).
Although we can’t list all the ways researchers use this search tool, we can say that, in general, researchers use BLAST to find out more information about a sequence. If a BLAST search matches your sequence, you will have a portal into all the available information about it, including various scientific databases, scientific publications and expression and protein information. If your sequence is not available in the organism you’re interested in, there’s a good chance it will match a sequence in a different organism. Because you can gain information about the homologous gene, BLAST is still valuable to you. Plus, if your sequence is a member of a gene family, you could gain information about its possible function, as a result of the motifs it shares with its family members. |
BRCA1 and BRCA2
| What it's not: |
R2D2’s twin cousins. |
| What it is: |
BReast CAncer 1 and 2 genes are examples of tumour suppressors that normally help to restrain cell growth. When these genes are mutated and inactivated, cells can grow too much and cancer develops. Someone who has inherited a mutation in BRCA1/BRCA2 has an increased risk of breast (for both women and men), ovarian or prostate cancer. |
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