A pair of chromosomes made up of two homologs. Homologous chromosomes have corresponding DNA sequences and come from separate parents; one homolog comes from the mother and the other comes from the father. Homologous chromosomes line up and synapse during meiosis.

In metaphase I of meiosis I, the pairs of homologous chromosomes, also known as bivalents or tetrads, line up in a random order along the metaphase plate. The random orientation is another way for cells to introduce genetic variation.

Autosomes

Autosomes undergo synapsis during meiosis, and are held together by a protein complex along the whole length of the chromosomes called the synaptonemal complex. This exchange produces a chiasma, a region that is shaped like an X, where the two chromosomes are physically joined.

Near the center of each chromosome is its centromere, a narrow region that divides the chromosome into a long arm (q) and a short arm (p). We can further divide the chromosomes using special stains that produce stripes known as a banding pattern.

Chromosomes come in matching pairs, one pair from each parent. Humans, for example, have a total of 46 chromosomes, 23 from the mother and another 23 from the father. With two sets of chromosomes, children inherit two copies of each gene, one from each parent.

There are 23 pairs of chromosomes in somatic cells; one member of each pair is paternal (from the father) and one maternal (from the mother).

Somatic cells are the cells of an organism that are not germ cells, or reproductive cells. Somatic cells are highly specialized and can be very different from one another. Some examples of somatic cells include nerve cells, skin cells, and blood cells.

220

Humans have 23 pairs of chromosomes–22 pairs of numbered chromosomes, called autosomes, and one pair of sex chromosomes, X and Y. Each parent contributes one chromosome to each pair so that offspring get half of their chromosomes from their mother and half from their father.

Chromosomes come in pairs. Normally, each cell in the human body has 23 pairs of chromosomes (46 total chromosomes). Half come from the mother; the other half come from the father. Two of the chromosomes (the X and the Y chromosome) determine your sex as male or female when you are born.

“Genes passed on by father tend to be more active than the same gene from the mother.” Tooth size, jaw size, and the shape of teeth are all genetic, and children can inherit these characteristics from either parent, according to research that appeared in the American Journal of Physical Anthropology.