Higher frequencies of B chromosomes
, plants with Bs, and all three B chromosome
variants were detected in Sichuan landrace populations, thus Sichuan is likely the origin of landraces in southwest China.
analysis and Y chromosome
microdeletion analysis were performed from peripheral blood sample.
In the new experiments, the mice lacked the gene because they didn't have Y chromosomes
A sex chromosome
that's present in every normal male body cell.
Geneticists from Ohio, California and Japan joined forces in a quest to correct a faulty chromosome
through cellular reprogramming.
Variations in other human chromosomes
, including the X chromosome
, make this an unlikely scenario.
The scientists have shown that chromosomes
fold in a series of contiguous "yarns" that harbor groups of genes and regulatory elements, bringing them in contact with each other and allowing them to work in a coordinated manner during development.
Normal human chromosomes
are linear in structure consisting of two "arms" (designated "p" and "q") that flank a single active centromere.
It was believed that all of the Mall elms had four chromosomes
To increase the production of this top shell, genetic and breeding information is crucial; therefore, the study of chromosomes
as the basis of genetics and breeding science is clearly important.
B or supernumerary chromosomes
are generally heterochromatic, fail to pair with the normal member of the complement (A chromosomes
) during meiosis (unlike most chromosome
mutations) and often show accumulation (i.
The B chromosomes
show instability during meiosis, but present preferential segregation for the nuclei which form gametes, and normal behaviour during the mitotic process, except in the second division of the microspores in the endosperm and tapetal cell, where they show high nondisjunction rates (RANDOLPH, 1941; RHOADES et al.
evolve more dynamically in sedges than in any other group of flowering plants.
True bugs, the Heteroptera, have many cytogenetic characteristics that make them unique among most insect groups: the possession of chromosomes
without a primary constriction, the centromere, namely holokinetic chromosomes
; a pair of <<m chromosomes
>> in 16 families, belonging to four infraorders; a different meiotic behaviour for autosomes and sex chromosomes
; and a mean chiasma frequency of only one chiasma per bivalent (Ueshima, 1979; Nokkala, 1986; Papeschi & Bressa, 2006).
Damaging mutations may be corrected through recombination, when chromosomes
from the mother sidle up to their counterparts from the father and exchange genetic material.