genetics
study of heredity
gamete
a haploid sex cell that is capable of fusion/fertilisation
haploid
cell has one set of chromosomes
diploid
cell has two sets of chromosomes
polyploid
having three or more times the haploid number of chromosomes
progeny
the offspring of a cross
F1
the first generation of offspring
autosomes
chromosomes that do not determine sexuality
genotype
the genetic make up of an organism
phenotype
the physical make up of an organism
gene
a part of a chromosome that controls a single characteristic or trait
chromosome
chain of genes made up of DNA
chromatin
when the cell is not dividing, chromosomes appear as long thin thread called chromatin
alleles
different genes that control the same trait and have the same locus on homologous chromosomes
multiple alleles
when more than two different genes control a single trait or characteristic
heterozygous
an organism that has two different genes controlling the same trait
homozygous
an organism that has two identical genes controlling the same trait
locus
the position of a gene on a chromosome
dominant
when an allele prevents its partner allele from having an effect on the trait. The weaker gene is said to be recessive
incomplete dominance
where neither allele is expressed in the phenotype of the heterozygous condition
the law of segregation
states that characteristics are controlled by pairs of factors, which segregate from each other during the forming of gametes, and are recombined after fertilisation
the law of independent assortment
states that either of a pair of alleles is equally likely to combine with either of another pair of alleles when gametes are being formed
sex chromosomes
X and Y chromosomes, XX= female, XY= male
sex linked
a trait controlled by a gene on the X chromosome
