Genetics
Experimental study of hereditary/genes
Gene
Fundamental unit of hereditary
Genome
complement of all genes for given organism. The genetic material of a chromosome
Mutation
A change in DNA sequence
allele
Alt form of gene( result from mutation)
genotype
The specific allele composition of cell
phenotype
The outward expression of a specific genotype
chromatin
the substance of chromosomes; now known to include DNA and chromosomal proteins
histone
a type of basic protein that forms the unit around which DNA is
coiled in the nucleosomes of
eukaryotic chromosomes
nucleosome
the basic unit of eukaryotic chromosome structure; a ball of eight
histone molecules that
is wrapped by two coils of DNA
chromatid
one of the two side by side replicas produced by chromosome replication
sister chromatids
the juxtaposed pair of chromatids arising from the replication of a chromosome
dyad
– a pair of sister chromatids joined at the centromere
tetrad
four homologous chromatids in a bundle in the first meiotic prophase and metaphase
chiasma
a cross-shaped structure commonly observed between nonsister
chromatids in meiosis; the
site of crossing over
homogametic sex
the sex with (homologous) homomorphic sex chromosomes
hemizygous gene
a gene that is present in only one copy in a diploid organism
null hypothesis
a hypothesis that proposes no difference between two or more data sets
recombination
the process that generates a haploid product of meiosis whose
genotype is different
from either of the two haploid genotypes
that constituted the meiotic diploid
recombinant gamete
– any gamete with a genotype that differs from the genotypes of the
two haploid
parents that fused to form the diploid meiocyte
parental gamete
any gamete with a genotype identical to one of the haploid parents
that fused to
form the diploid meiocyte
Telomore
chromosome end
Heterochromatin
dense chromatin