Leaving cert Biology Genetics

a sex cell, they are haploid cells which are capable of fusion e.g. sperm and egg

The fusion of two gametes to form a single cell called a zygote

• The section of DNA which codes for a protein
• Gene's are represented by letters

Different forms of the same gene

The positon of a gene in a chromosome

Means that the allele prevents the recessive allele from being represented

The allele is prevented from being expressed by a dominant allele

The genetic makeup of an organism, the gene's that are present

The offspring that are produced

The two alleles are identical

The two alleles are different

Neither the allele is dominant or recessive with respect to the other. Both alleles are equally expressed in the heterozygous genotype to produce an intermediate phenotype

A diagram showing the genetic history of a group of related individuals.

Nonsex chromosomes

1 pair

XY

XX

Involves the study of a single characteristic

Involves the study of two chracteristics

Genes are located on the same chromosome

A characteristic is controlled by a gene on a sex (x chromosome)