Genetic Variation Flashcards
Asexual
reproduction
Reproduction involving only one parent. Doesn’t produce genetic variation.
Allele Frequency
The number of each allele in a population or a gene pool.
Alleles
Alternative form of a gene (eg blue eyes or brown eyes)
Chiasma
Point of contact, the physical link, between two (non-sister) chromatids belonging to homologous chromosomes during crossing over
Crossing Over
Occurs during meiosis, when the homologous chromosomes line up at
the equator, and exchange genetic information. Leads to new combination of alleles.
Co dominance
When both alleles are equally dominant and both are expressed in the offspring if present.
Complete
dominance
A form of dominance where the allele that is regarded as dominant completely masks the effect of the allele that is recessive
Diploid
A cell or an organism consisting of two sets of chromosomes: usually, one set from the mother and another set from the father
Dominant Allele
An allele which is always expressed in the phenotype if it is present as it will mask any recessive allele.
Evolution
Is the change in the characteristics of a species over several generations and relies on the process of natural selection.
Fertilizations
A process in sexual reproduction that involves the union of male (sperm) and female (ovum) gametes (each with a single, haploid set of chromosomes) to produce a diploid zygote
Founder effect
when a small number of individuals from an existing population moves to another area and establishes a new population and it becomes reproducibly isolated from the original population.
Fitness
The ability of an individual to survive and reproduce.
Genetic Drift
Random change in allele frequency due to chance.
Genetic Variation
Is the differences or the diversity in the genetic makeup in a population
Gamete
Sex cell of an organism e.g. sperm, egg, pollen or ova. A haploid sex cell.
Genotypic Ratio
A ratio showing the probability off the offspring in a particular cross having a possible phenotype.
Gene
A length of DNA that holds the instructions for a characteristic. A sequence of bases (in DNA) that code for a particular trait
Gene pool
The total alleles in a population.