VOCAB LIST FOR GENETICS AND VARIATION
WORD
Adenine
Allele
Autosome
Centromere
Chiasma
Chromatid
DEFINITION
One of the bases present in nucleic acids
One of a number of alternative forms that a gene can take
Non-sex chromosome
The part of a chromosome which attaches to the spindle fibres during cell division
the point where two chromatids exchange genetic material
One of the two strands produced by replication of a chromosome, held together at the centromere
Chromosome
A length of DNA consisting of many genes
Chromosome
mutation
A change in the genetic material of the chromosome that can be inherited
Crossing over
The mutual exchange of pieces of chromosome where groups of genes can be swapped
Cytocine
One of the bases present in nucleic acids
Deletion
A mutation in a chromosome where a section is removed, or in a gene, where one of the bases is removed from
the sequence
Dihybrid
Looking at 2 traits
Diploid
Having 2 sets of chromosomes, two of each kind
DNA
Dominant
The genetic material of all organisms except some viruses
The allele that is expressed whenever it is present in an organism
Double helix
The form that DNA takes. It is 2 strands of DNA that are joined together through base pairing of the nucleic acids
Duplication
A section of chromosome is lost and is added on to is homologue
Gametic
Gene
Gene mutation
Occurring in sex cells
A segment of DNA that codes for a polypeptide
A change in the genetic material of the gene that can be inherited
Genome
The entire set of genes of an organism
Genotype
The genetic makeup of an organism
Guanine
One of the bases present in nucleic acids
Haploid / monoploid
Having one set of chromosomes
Heritable variation
Heterozygous
Histone
Homologous pair
the differences among individuals in morphology, behaviour, and reproductive performance that have a genetic
basis
Having two different allelic forms of a given gene
A protein around which DNA will wrap
A pair of chromosomes that are identical to eachother and line up together during cellular division
Homozygous
Having two of the same allele
Independent
assortment
The random shuffling of chromosome pairs to produce a huge variety of gametes in a single individual
Insertion
Locus
When an extra base is inserted into the polypeptide chain during copying
Position on a chromosome occupied by a gene
Meiosis
A form of cellular division to provide haploid cells, concerned with reproduction
Mitosis
A form of cellular division to provide diploid cells, concerned mainly with cell growth and repair
Monohybrid
Formed by crossing two pure-bedding parents differing with respect to one pair of contrasting traits
Mutagen
An agent that causes a mutation
Mutation
A change in the genetic material that can be inherited
Nucleotide
Sub-unit of nucleic acid
Phenotype
The physical expression of gene, what an organism looks like
Recessive
An allele that is expressed only when there are two of the same present
Recombination
When a section of a chromosome is exchanged with a section in its homologue during meiosis
Semi-conservative
Replication of DNA when only half the daughter DNA molecule is “new” the other is “old”
Sex chromosome
Chromosome that determines the sex of an individual
Somatic
Substitution
Cells of the body
A form of gene mutation where one base is traded for another
Test cross
Method of determining an organisms genotype, by crossing it with a homozygous recessive
Thymine
One of the bases present in nucleic acids
Translocation
The movement of a group of genes between chromosomes