Genetics and DNA Glossary
alleles:
Different versions of the same gene.
asexual reproduction:
This type of reproduction only requires one parent, it does not involve gametes. All the
carrier:
A person who does not show symptoms of the disease but carries the recessive gene for that
chromosomes:
These are found in the nucleus of a cell. Human body cells have 46 chromosomes.
clones:
Genetically identical to their parents.
continuous variation:
A feature that can vary, for example, height or weight.
cystic fibrosis:
An inherited disease that results in the production of too much thick, sticky mucus.
denatured:
discontinuous
variation:
DNA:
A term used to describe the altering of the active site on an enzyme.
dominant gene:
The gene that shows up as a characteristic in an organism.
double helix:
The twisted shape that DNA takes.
endangered:
If a species is endangered, there are only a few of them left in the world.
enzymes:
These are biological catalysts and assist in chemical reactions.
extinct:
There are no more of these organisms left in the world.
gametes:
These are the sex cells, sperm and egg.
genes:
Made up of DNA. They control an organism’s characteristics.
gene bank:
A store of genetic information to help prevent extinction.
genetic engineering:
A technique to change an organism’s characteristics by changing a gene.
genetics:
The study of genes.
genotype:
A description of the genes of an organism.
heredity:
The passing of genes from parents to offspring.
natural selection:
A term attributed to Charles Darwin whereby the organisms with the characteristics most
nucleus:
The central part of a cell, which contains chromosomes and genes.
phenotype:
A term used to describe the appearance of an individual.
polydactyly:
An inherited condition in which a person has an extra digit on a hand or foot. It is caused
Punnett square:
The Punnett square is a diagram used to predict the outcome of a particular genetic cross.
recessive:
The gene that only shows if the offspring contains the two alleles for this characteristic.
selective breeding:
A process in which humans try to develop varieties of animals or plants with desired
sexual reproduction:
A type of reproduction that involves gametes and leads to variation in the offspring.
variation:
The differences between organisms.
offspring will be genetically identical.
disease, which they may pass onto their offspring.
Variation where there are limited options, for example tongue rolling - you can either
tongue roll or you cannot.
Deoxyribonucleic acid, found inside the nucleus, carries the genetic information.
suited to their environment are more likely to survive and pass on their genes.
by a dominant gene.
characteristics.