GENBIO - Inheritance of Traits & Mendel's Law of Inheritance - Genbio

diploid

result of the union of haploid egg cell and haploid sperm cell

science of genetics

studies how these characteristics are inherited

chromosomes

made up of DNA molecules coiled around histones

sequence of DNA bases

determine the codes for proteins responsible for observable characteristics

gene

used to describe a specific sequence of DNA

meiotic cell division

where chromosomes are halved and passed on from the parent cell to the daughter cells

genome

set of all genes found in a cell

paternal and maternal sets

the two sets of chromosomes a genome is composed of in sexually reproducing organisms:

23 pairs

amount of homologous pairs in diploid individual:

homologous chromosomes

pair of paternal and maternal chromosomes that are of the same size, similar gene locations, common banding patterns, and same centromere location

alleles

one of two or more alternative forms of gene

genotype

totality of the genetic makeup of an individual

genotype

specifically refer to the combination of alleles found in a homologous chromosome

phenotype

observable expression of a particular genotype

homozygous genotype

two similar alleles are present in a pair

heterozygous genotype

two different alleles are paired

dominant allele

allele that is expressed in a heterozygous condition

recessive allele

allele that is not expressed

Gregor Mendel

Augustinian monk who first illustrated the basic pattern of inheritance of characters from parents to offspring

garden peas (Pisum sativum)

plant that Mendel used to show “factors of inheritance”:

genes

modern equivalent of “factors of inheritance” (by Mendel)

Reginald Punnett

made the Punnett square

law of segregation

• separation of homologous chromosome during gamete formation, including the alleles contained in it

• Mendel’s first law

law of independent assortment

• second law of heredity

• a pair of alleles will segregate or assort independently from other alleles during gamete formation

1. unit factors in pairs

2. dominance and recessiveness

3. segregation

4. independent assortment

Mendalian postulates