An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene. An organism which has two different alleles of the gene is called heterozygous.
When homologous chromosomes have different alleles on them is called?
Heterozygous (and its less common form heterozygotic) means “relating to a cell that has two different alleles for a particular gene at corresponding positions on homologous chromosomes.”
What is it called when both chromosomes have different allele variations?
If the two alleles are the same, the individual is homozygous for that gene. If the alleles are different, the individual is heterozygous.
Can homologous chromosomes have different alleles of a gene?
In biology, homologous chromosomes are paired chromosomes. They essentially have the same gene sequence, loci (gene position), centromere location, and chromosomal length. Although they may have the same genetic sequence and loci, they may differ in alleles.
What does it mean when two sets of chromosomes are homologous?
The two chromosomes in a homologous pair are very similar to one another and have the same size and shape. Most importantly, they carry the same type of genetic information: that is, they have the same genes in the same locations.
What is Nonsister chromatid?
A non-sister chromatid refers to either one of the two chromatids of paired homologous chromosomes. During prophase I of meiosis I, the non-sister chromatids of (homologous chromosomes) form chiasma(ta) to exchange genetic material.
How do alleles relate to homologous pairs?
So allele and homologue, these words are not synonymous ; but yes, alleles are always present on homologous chromosomes. One member of a homologous pair comes from father while another member comes from mother.
What does hemizygous refer to?
Listen to pronunciation. (HEH-mee-ZY-gus) Describes an individual who has only one member of a chromosome pair or chromosome segment rather than the usual two. Hemizygosity is often used to describe X-linked genes in males who have only one X chromosome.
What is the term heterozygous mean?
(HEH-teh-roh-ZY-gus JEE-noh-tipe) The presence of two different alleles at a particular gene locus. A heterozygous genotype may include one normal allele and one mutated allele or two different mutated alleles (compound heterozygote).
What means haplotype?
A haplotype is a group of genes within an organism that was inherited together from a single parent. The word “haplotype” is derived from the word “haploid,” which describes cells with only one set of chromosomes, and from the word “genotype,” which refers to the genetic makeup of an organism.
What is a homologous pair How do the homologs differ?
Explanation: Although both are very similar, the difference between the two is the pairing. Homologous chromosomes are basically two similar chromosomes inherited from father and mother. They are homologous because they have the same genes, though not same alleles.
What does the term Tetrad mean?
Medical Definition of tetrad
: a group or arrangement of four: as. a : a tetravalent element, atom, or radical. b : a group of four cells arranged usually in the form of a tetrahedron and produced by the successive divisions of a mother cell a tetrad of spores.
What’s the difference between alleles and homologous chromosomes?
Your cells have two sets of chromosomes, called homologous pairs. These chromosomes have the same genes, but might have different versions of those genes. The different possible versions of the genes are called alleles.
Which term is used to describe the way homologous pairs of chromosomes line up at random?
What term is used to describe the way homologous pairs of chromosomes line up at random orientation during Metaphase I? Independent assortment; daughter cell randomly inherits either the maternal or paternal chromosome from each pair.
What occurs while homologous chromosomes are paired up?
Synapsis is the pairing of two chromosomes that occurs during meiosis. … When homologous chromosomes synapse, their ends are first attached to the nuclear envelope. These end-membrane complexes then migrate, assisted by the extranuclear cytoskeleton, until matching ends have been paired.
When are homologous chromosomes separated?
In anaphase I, centromeres break down and homologous chromosomes separate. In telophase I, chromosomes move to opposite poles; during cytokinesis the cell separates into two haploid cells.