Homologous chromosomes are made up of chromosome pairs of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci. One homologous chromosome is inherited from the organism’s mother; the other is inherited from the organism’s father.
Are homologous chromosomes identical in shape and size?
Homologous chromosomes form a pair, one from each parent. Homologous chromosomes are similar in size and shape, and contain the same genes, though they may have different alleles.
Are homologous chromosomes different sizes?
The two chromosomes in a homologous pair are very similar to one another and have the same size and shape. … Aside from small regions of similarity needed during meiosis, or sex cell production, the X and Y chromosomes are different and carry different genes. The 44 non-sex chromosomes in humans are called autosomes.
What is the same in all parts of homologous chromosomes?
Homologous chromosomes are similiar but not identical. Each carries the same genes in the same order, but the alleles for each trait may not be the same. … The maternal and paternal chromosomes in a homologous pair have the same genes at the same loci, but possibly different alleles.
What happens if a human has an extra chromosome?
For example, an extra copy of chromosome 21 causes Down syndrome (trisomy 21). Chromosomal abnormalities can also cause miscarriage, disease, or problems in growth or development. The most common type of chromosomal abnormality is known as aneuploidy, an abnormal chromosome number due to an extra or missing chromosome.
Why are chromosomes different sizes?
As a result of either unequal growth or unequal division, corresponding chromosomes of different cells within the same individual vary in size.